NZAS from the air

New Zealand’s Aluminium Smelter




Production (Rio Tinto share)





2023 figures


New Zealand’s Aluminium Smelter (NZAS) converts alumina into aluminium using renewable hydroelectricity, resulting in one of the lowest carbon footprints for an aluminium smelter in the world.

The smelter is located on Tiwai Peninsula in Southland and the majority of the plant's alumina is supplied from our Yarwun and Queensland Alumina Limited refineries. Around 90% of the aluminium produced at NZAS is exported.

NZAS is a joint venture owned by Rio Tinto (79.36%) and Japan’s Sumitomo Chemical Company (20.64%).

The power supply arrangement for the smelter is set to expire in December 2024. But we’re working closely with Ngāi Tahu, Southland and key industry leaders to find the best way for the smelter to continue operating and contributing to the local and national economies beyond 2024.

Our partnerships

In 2022, we signed a Memorandum of Understanding (MoU) with Ngāi Tahu – the primary iwi with guardianship responsibilities over the South Island of New Zealand – which focuses on positive environmental outcomes for NZAS.

The agreement lays a path for us to work together on plans to remove waste, conduct environmental monitoring, and remediate NZAS – a priority for both mana whenua and Rio Tinto.

We have also identified 34 cultural heritage sites located on land owned and managed by the smelter. They include European burials and structures, as well as Māori sites such as middens, ovens, burials and an adze workshop. Wahi tapu, wahi taoka and mahinga kai are also present on Tiwai Peninsula. We have a Cultural Heritage Management System Plan in place to look after these important sites.

Latest NZAS releases

Low carbon aluminium

NZAS is proud to have its metal marketed under Rio Tinto's RenewAl brand. As the world moves towards a lower carbon future, the RenewAl brand can help NZAS take advantage of growing demand for high-quality aluminium to be used in more sustainable, low-carbon products. RenewAl certifies NZAS metal as being some of the lowest carbon in the world.

In 2024, NZAS was Provisionally Certified under the Aluminium Stewardship Initiative (ASI) Performance Standard V3, and is transitioning to compliance over the next year. NZAS is ASI Chain of Custody Certified. This means we support responsible production of aluminium.

Working at NZAS

NZAS communities

We strive to establish and maintain community relationships that positively contribute to the quality of life where we live and work, and by supporting partnerships that are mutually beneficial and deliver long-term, sustainable results.

We have been the major sponsor of the annual NZAS Southland Science & Technology Fair since 2003. Students are required to investigate a topic of their choice using a scientific method of hypothesis, method, test and conclusions.

We also have a longstanding partnership with Southland Girls' High School, designed to encourage students to pursue careers in engineering and science. Each year we host students at the smelter for a week so they can learn about career options and work on a project gathering, testing and analysing data. Almost half of the participants have gone on to study engineering at university.

In addition to offering in-kind support, NZAS also donated $480,353 in 2023 to 32 non-profit organisations in the Southland community.

As part of our agreement with Ngāi Tahu, in 2023, NZAS and Ngāi Tahu awarded $1.15 million in support to 7 local cultural and business projects.

Increasing diversity

We’re committed to an inclusive environment where people feel comfortable to be themselves. We want our people to feel that all voices are heard, all cultures respected and that different perspectives are welcomed and valued.

Tiwai is a place where we treat each other fairly and with dignity regardless of race, gender, nationality, ethnic origin, religion, age, sexual orientation or anything else that makes us different.

We want a diverse workplace – not only because it is good for our business, but because it is the right thing to do.

Sourcing locally

We strive wherever possible to buy locally and employ locally, investing in our community by supporting economic activity and contributing towards a sustainable future.

We also focus on training, apprenticeships and employment opportunities. Our graduate program is designed to attract and develop employees to bring fresh thinking, different perspectives and new skill sets.

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Discover more about life at Rio Tinto

NZAS contacts

Contact NZAS

Tiwai Road
New Zealand

T: +64 3 218 5999

Postal address

Private Bag 90110
New Zealand

Community enquiries

E: NZAS Community Enquiries
T: +64 3218 5440