The Tiwai Point aluminium smelter is running flat out, and the combination of full production and a surge in world prices is showing up in New Zealand's export figures.

Rio Tinto's most recent operations review reported the smelter "at full capacity rates", producing 83,000 tonnes of aluminium in the June quarter and 165,000 tonnes in the first half of 2026. That compares with 149,000 tonnes in the first half of last year, when the plant was still ramping back up.

Stats NZ's overseas merchandise trade figures for August show aluminium exports up $80 million, or 58 per cent, on August last year, to $219 million. The Press, which analysed the data, put the value of the country's aluminium exports at about $2.2 billion and reported the average value per tonne in August at roughly $6200, against about $4800 a year earlier. The statistics agency's category covers aluminium and aluminium articles broadly, so not every dollar can be traced to Tiwai, but the plant near Bluff is New Zealand's only aluminium smelter.

Metal market analysts have linked the price rise to conflict in the Middle East. The Gulf region accounts for about 9 per cent of global smelting capacity, and the London Metal Exchange cash price rose from about US$3157 a tonne on 27 February, the day before the conflict began, to US$3855 by early June. Rio Tinto's average realised aluminium price across its global business jumped 39 per cent in the first half.

Exports and earnings

The smelter, operated by New Zealand Aluminium Smelters and owned by Rio Tinto through Pacific Aluminium, can produce more than 335,000 tonnes a year with its three operating potlines, and about 90 per cent of its metal is exported. It produced 314,936 tonnes of hot metal in 2025, up 8.7 per cent on 2024, and Pacific Aluminium (New Zealand) reported a net profit of US$176 million for the year.

Power is locked in. Electricity contracts run to 2044, and the company's accounts show hedges covering a fixed supply of 572 megawatts over that period, though it notes that long-term power price forecasts remain uncertain.

Fourth potline

The next step would be restarting Line 4, idle since 2020. Rio Tinto and Contact Energy signed a non-binding letter of intent in May for a power purchase agreement that could support a restart from 2030, adding about 30,000 tonnes a year of production and roughly $100 million a year in export revenue. The proposal would require about 50 megawatts of additional supply and is tied to Contact's planned Southland Wind Farm, which won fast-track consent in April and awaits a final investment decision expected in 2027.

The smelter's wider footprint in the region was set out in a socio-economic impact assessment released in July, and in August the NZAS–Ngāi Tahu Community Development Fund awarded about $367,000 to 10 community, environmental and cultural projects across Murihiku.

For Southland, the arithmetic is simple. Every month the smelter runs at capacity while prices hold at these levels, more money flows through Bluff's wharves, where aluminium is one of South Port's biggest cargoes, and into the regional economy.