All right, good morning everyone. Philip Cory-Wright, Chair of South Port. I'm joined by Lara Stevens, who's the Chief Financial Officer, and Geoff Finnerty, who's the Port General Manager, who's standing over to my Nigel Gear, our CEO, who's had a close family bereavement, so isn't joining us this morning. Sorry we're a little bit late, but hopefully the news that we can deliver through this presentation will make up for it. I think it's been a very positive year for South Port. We've had a record profit, and that's been driven by top-line growth in tonnage to a record number, up 10.6% to 3.5 million tonnes. That's translated down into the earnings before interest, tax, depreciation, and amortization. That's up 21% to $25.8 million, and driven partly by a margin increase of 300 basis points to 41%.
At the bottom line, on a technical net profit after tax basis, it's up 80.6% to $3.32 million, and on a normalised basis, it's up 39.5% to $3.89 million. That's been driven primarily by Southland's export sector, which is reflected both in terms of imports of stock food and fertilizer and exports. A second bit of good news was the decision by New Zealand Aluminium Smelter at Tiwai to enter into a 20-year power purchase agreement with major generators. That's had two big effects. They account for roughly 20% of our profit, as we've previously advised, and 30% of our trade volume. It provides certainty about our anchor customer going forward, which really gives the confidence to the port moving forward.
It also creates cargo opportunities, and examples being potential containerization of the aluminium more than has been historically, but also new energy into the province to drive increase in production of the smelter. Specific examples of that are the Mercury Kaiwera Downs Stage 2 wind farm, which turbines come through the port expected starting, I think, in October. That's a significant item. Whilst it's a one-off item, because they only come through once, we're sufficiently confident with other prospects that that's going to be an ongoing benefit to the port. One of the good things about South Port, as the graph will show, is that we're well balanced between exports and imports, and that provides some stability to our earnings platform.
None of this would have been possible without having an engaged workforce, and we've worked very hard with the management team over the last 12 months in particular on improving our interactions onto health and safety, and I think that's been reflected in results. The last bit of good news is that we've announced an increase in dividend to $0.205 for the interim dividend, taking the full dividend to $0.28 per share, which is just up $0.01. That's well covered by operating cash flow and provides South Port with the funds to enable its position for cargo growth. I'll hand over to Geoff Finnerty, the Port General Manager, to take us through.
Good morning everyone. I just want to focus a little bit more on our people. Our people have a successful business that requires the input from successful people. I know over the last 12 months, we've put a lot of effort and energy into growing our people as our business grows. We've also focused a lot on health and safety, as Philip mentioned. It's safety first as our number one company value. Over the past 12 months, in particular, we've been focusing a lot on our critical risk controls, our overlapping duties, and traffic management. Now, I'm just going to touch on some aspects of the business operation in the coming slides. As Philip mentioned, we've had a record net profit after tax of up 81%, $13.3 million on the back of record trade of 3.55 million tonnes.
We also have a very strong operating cash flow across that period and also have moved back into more of a maintenance CapEx level of spend after a significant period over the last two or three years of growth CapEx being reinvested in the business to set the business, give the business a good platform for future development. Bulk cargo makes up 85% of our overall 3.55 million tonnes. Looking at our 10.6% increase in cargo volumes, as I said, 85% of our cargo volumes are made up from bulk cargo. Interestingly, when we look at this slide, we can see the impact of the demand response activation of the smelter. The smelter is dropping its cargo volumes by 20% or about 200,000 tonnes, but offset by quite a significant increase in cargo crossing our berths on the Bluff side of the harbor.
What I'd like to highlight on this slide is that, again, our operating revenue, our increase in operating revenue of 12.7%. Looking across to the right-hand side of that slide, top normalized net profit after tax, and the strong relationship or the strong leverage we have from our operating revenue producing a strong net profit after tax, which has been helped obviously by significant cargo volumes increases in the agricultural sector, but also the mix of those cargoes, the type of cargoes that have been moving through the port. The other things I'd just like to touch briefly on this slide is our modest increase in total assets. I think that reflects the fact that we have been through this growth period or growth CapEx investment period over the last two or three years, and we're moving back into more of a maintenance CapEx position at this point.
Also, the other item I'd like to touch on on this slide is the reduction in our net debt, which is a result of less cash required for CapEx, but also indicates the strength of the cash flow that South Port has. If you look at the far right of the graph that's now on screen, you can see that we've had a record year of volume through the port. Interestingly, the yellow bar on that indicates the reduction that we've had in the smelter room foot. Again, just reinforcing the fact that 85% of our cargo is bulk cargo. I think that the remainder of that is made up by a container operation and a 15% total cargo volume in that space.
I think what we can see here is the port reflects the wider Southern economy, and the growth that we've seen in our cargo movements through the port reflects the strong growth in the agriculture sector, particularly in the Southern region. As Philip mentioned in the introduction, we have a really good mix. If you look at the top graph on the right-hand side, a really good balance of imports and exports through our business. The imports, sorry, are in support of the agricultural sector, so that's things like stock food, fertilizer, and fuel. The export is driven mainly by the forestry sector, but also through N ZA S product moving across our berths. The volume mix has also been reflected in the bottom graph there, and the imports that that plays on our revenue per tonne.
You can see that we've had quite a good growth in our revenue per tonne for bulk cargo. That's the result of the cargo mix again, but also the GRI increases that we've been able to obtain over the last 12-month period. Also, the impact of the Kia Whakaū infrastructure channel of port deepening project and the levy that's been created as a part of that introduction of that project. The wet spring has had, the wet spring of Southland had quite a significant impact on some of the cargoes that were moving through the port, particularly in the stock food space. The wet spring in FY 2025 slowed down the grass growth in the region, which then led all the agricultural sector to move across to imported stock food to keep their milk production up.
We also saw a good recovery in the sheep and beef sector, which had an impact on fertilizer application, which had been at lower levels in previous years because of the performance that was going on in that sector. We're seeing our fertilizer volumes probably start to move back to more traditional levels within the region. 17% of our cargo movements are made up by container movements through the port. South Port has had the pleasure of being able to service MS C since 2008. I've been a strong supporter of Bluff as a port, but Southland as a region. There are critical container connections for Southland to the world. Our container volumes are mostly export-driven and in support of the agricultural and manufactured products that are produced within the region.
The next slide just gives you a bit of a breakdown of the key components or key products that are made up of our container volumes. You can see that we've got meat, dairy, and manufactured products. A lot of that manufactured product, of course, is smelter activity. We've seen a slight decrease in the dairy exports across that period, and that's just a reflection of the wet spring in FY 2025. In the next slide, you can see the impact that the demand response has had on the product that's moved via the smelter. We've seen a 20% reduction because of that, of products that have been moving across the smelter wharf. We're now seeing that the smelter has been busily restarting the potlines that were affected by the demand response request.
We are expecting that those potlines will be moved, or the volume, sorry, being moved by the smelter, either import or export, will be brought back up to in line with product being moved across the wharf in previous years. We're expecting those volumes to get up to close to a million tonnes. We're recovering that 200,000 tonnes across that period. We've had a 20-year commitment, sorry, it's been pleasing to see the 20-year commitment to the smelter for future through to 2044 with their eligible supply contracts. The port itself has had a 54-year relationship with the smelter, and it's been a strong relationship across that period. They're an excellent sea-based cargo for the port and produce a significant amount of the marine activity that goes on the port to service the product that comes and goes from the smelter.
It's interesting to note the diversification that's occurred in the type of cargo that have been moving through the port. If you look at the slide, you'll see in 2010, cargo moving through the port, the smelter produced 60% of the cargo that moved through the port. Over the last 15 or so years, we've seen that the reliance on the smelter reduce, with this year, the total volume through the port representing 23% of cargo movement.
Tēnā koutou. I'm just going to comment on some of the financial performance reports for the year. Our total operating revenue was up by 13% on FY 2024, up $7 million on the prior year. As Geoff and Philip have both mentioned, this was driven by strong bulk cargo volumes through the port and also helped by the implementation of an infrastructure levy related to our capital dredging campaign, the Kia Whakaū project. This has really helped to drive an increase in revenue growth per tonne. In regard to EBITDA, if you look at the orange line on the graph, this shows our EBITDA over the past several years, EBITDA margin. Our operating leverage is demonstrated with the increase in our EBITDA margin over the last 12 months. We have a relatively fixed cost base being an infrastructure business, and this has been spread across higher volumes.
If you look at the increase in revenue by 13% and then you convert that to an EBITDA increase by 21%, that just shows the leverage that we've got. We've seen an increase in compliance costs in recent years, which has really impacted this margin. If you look back to FY 2022, it was slightly higher than it is at the moment. However, South Port's EBITDA margin for FY 2025 at 41% is still above the New Zealand port sector average of around 32%. Turning now to our normalized net income after tax, we had a record underlying impact of $13.9 million, reflecting a 39% increase on the prior year. When thinking about underlying profit versus our reported profit, it's more sensible for us to compare the movement in the normalized or underlying profit, given the reported profit for FY 2024 included some one-off adjustments, including quite a large adjustment to our tax provision.
Turning now to our balance sheet, our gross debt reduced by $5 million during the year, with cash reserves maintained due to our Treasury policy guidelines. Our net debt to EBITDA of 1 highlights our strong financial health at the port. We had strong growth in our operating free cash flow for FY 2025, which was aligned with our operating results. South Port strives to have a shadow investment-grade credit rating, and this demonstrates prudence. Looking at our infrastructure investment cycle, you'll see in the graphs below that we have got over a period of significant capex and infrastructure maintenance spend. We are past a peak, but we could see another increase in growth CapEx in future years, depending on some of the future projects that are there that the port could potentially take advantage of.
The investments known have been both customer beneficial with efficiency gains, as well as port beneficial with extra charges put in place to ensure that we gain a secure and adequate return on the capital that we invest. Due to the dredging campaign and other investments, we've seen record tonnages being imported and exported through the port on ships. Deeper draft has allowed full vessels of fertilizer and wood chips to come in and leave the port. Thinking about our capital management, when we think about capital management, we constantly consider our reinvestment needs and the appropriate level of distributions to our shareholders to ensure that we get the right balance. When investing in growth CapEx, as I said, we always undertake extensive modeling to ensure that we can secure an adequate return before we'll invest in that capital.
Turning now to our dividend, South Port has a history of taking a consistent long-term approach to paying dividends. At this year, we are pleased to report a $0.01 per share increase in our dividends for FY 2025. Our dividend is always well covered by our free cash flow, even in times of downturns.
I'm just going to turn to our dredging journey, the Kia Whakaū project that we have implemented over the last few years. Just as a recap, the map that you can see on screen at the moment gives you a view of where the dredging occurred. The red area is our channel, our entrance channel, and that's a granite rock bottom, which creates the challenges when we look at deepening our channel. The orange areas are the swing basins and berth pockets. Overall, we had around about 160 cu m of rock or sand to remove as part of the dredging project. Prior to the dredging project completion, our maximum draft at the port was 9.7 m, and that was declared in the early 1980s when the last dredging campaign occurred.
The timeline that you see on the screen at the moment just demonstrates when the project kicked off, how we went about the project, and when we declared our revised 10.7 draft in 2024. What I would say as we went through this project is that we had really strong support from the community and the region with completion of the project. This slide just demonstrates the good news story that we've had with this project. We had a budget or an expectation of what the project might cost. You can see that the total project estimated cost in 2017 was just a little bit over $17 million. The good news is that project came in under budget at just a little bit under $13 million. It was a very successful campaign, which was completed under budget and on time.
The additional one-meter draft that we're seeing since the implementation and declarations has been getting used regularly by cargo movers through the port over the past 12 months. It's been a win-win situation for customers, but also for the port, given it's given a lot more flexibility around when vessels can move in and out of the port, creating efficiencies for cargo movers, and has allowed larger parcels of cargo to be able to move either in or out of the port as we move forward. It's definitely been a good news story for our customers, but also for ourselves in the fact that we've been also recovering the cost of that project through our infrastructure levy, which is calculated on a tonne-by-tonne basis as the product moves through the port. Looking forward now, agriculture is something that the government has focused on growing.
They have a strategy to grow agriculture exports from New Zealand up to that $3 billion level. A lot of that additional activity has been targeted in open agriculture. Locally in Southland, there are three projects being explored currently. One in Waitākere , a project which is listed under FastTrack approval, the government consenting process. We've also got Sanford and ocean ponds, New Zealand, exploring consenting possibilities for aquaculture activity. We're also interested in the land-based operations for aquaculture growth as well. The port's continuing to monitor developments in this area and is working closely with stakeholders to understand what future port services may or will be required to support the industry development over the years to come.
Thanks, Geoff. Yeah, so one part of the growth story is the agriculture, and it's not a short-term, but it's certainly a medium-term, very material prospect for us. The second one, as I mentioned in the introduction, was driven partly by the smelter certainty, but also some other opportunities, and that is the energy space. As a former director of a wind farm, it's pretty exciting to look at the prospects for Southland from wind farms. Specifically, already in place is Kaiwera Downs Stage 2, which Mercury, we've listed a couple of others that Contact and Manawa Pioneer have contemplated. There's another one, Mahina-a-Rangi , which is further north, that is also consented and looking at being brought forward.
Watch the space, but from the port's perspective, we've created space on the port for those wind farm turbines to be, that they're very large, to be imported through the port. I think the customers have been very happy with how we've performed to date. It's very good cargo, and I think it's a win-win for the customer and for the port. Speaking of space on the port, we've built out basically the 40 ha we've got on the port. We haven't got a graphic here, but we've basically tar-sealed pretty much the last little bit on the corner of the Island Harbour. With the growth prospects for cargo in the province, we've been giving thought as a board and management team to how do we position the port for growth in the future. Obviously, that tends to have a long-term focus.
None of this is probably going to happen in the extremely short term, but it won't happen unless we start planning for it now and engage in partners like Ngāi Tahu and our local community in a discussion around what we can and can't do and how we might best do it. That's something we've been giving active consideration to. It's probably not going to require large capital commitments in the short run, but it does probably provide, necessitate looking at consenting and looking at design options. That's what we are going to spend the next little time focusing on. In terms of just outlook for the business, I think we've painted a pretty positive picture. It's certainly an outstanding story for Southland. It's based on the two, the early million, but also the export agricultural sector, and hopefully increasingly the agricultural sector.
I think in terms of an outlook, we're not given a specific forecast today, but in terms of the shape of the business, it's a relatively steady state on the trajectory that the business has been heading in over the last 12 months. As Lara mentioned, we've gone through a hump of spending money both on maintaining our facilities like our access bridge and also some growth CapEx. It'll be a relatively steady state, but in an old asset like our port, there will always be things that we need to spend money on, and not all of which we can predict. Everything else being equal, we think the future looks pretty bright for both the province, our customers, and the port.
Maybe if I just summarize a really good result, record result, we've got a hole in the form of the smelter, which provides a basis for an anchor tent, if you like, for the business going forward. We've got good resilience and diversity in terms of our cargo mix. I mean, I think our biggest cargo is logs, which is roughly 35% of the port. We've got well-diversified both imports and exports. We've got a dividend that's well covered by our operating cash flow, creating enough money for us to capital to position the company going forward. I think we're anticipating that the continued positive outcome for exports, in particular for the province, is going to underpin our growth going forward.
We currently have no questions in the Q&A section. If anyone would like to post any questions in the next couple of minutes, you're welcome to do so. Thank you for your time today. We hope you found this presentation informative, and we look forward to keeping you up to date with what's happening at the port.