Case Brief: Trans-Tasman Resources Limited v The Taranaki-Whanganui Conservation Board [2021] NZSC 127

March 7, 2024


The Supreme Court unanimously confirmed the High Court’s decision to quash resource consents granted to Trans-Tasman Resources Limited (“TTR”) to mine iron sands in the South Taranaki Bight.


To mine the iron sands, TTR required consents under the Exclusive Economic Zone and Continental Shelf (Environmental Effects) Act 2012 (“EEZ Act”). The Environmental Protection Authority’s decision making committee (“DMC”) authorised TTR to extract up to 50 million tonnes of sand per year for a period of 35 years. As part of this process, de-ored sand would be discharged back to the seabed.

The Taranaki-Whanaganui Conservation Board is a collection of interested parties who opposed the DMC’s granting of consents. Their concerns included the environmental effects on the seabed and existing interests such as mana moana of local iwi. They successfully challenged the DMC decision in the High Court, and TTR’s subsequent appeal to the Court of Appeal was dismissed. TTR was granted leave to appeal to the Supreme Court.

The Case

Decision-making criteria

The majority in the Supreme Court held the EEZ Act prescribed an environmental bottom line to prohibit marine discharge if the environment could not be adequately protected through remedy or mitigation. It was not open for the DMC to grant a consent for the dumping of sand unless it was satisfied the activity was unlikley to cause material harm to the environment. The DMC should have addressed this consideration separately, and erred in law by failing to do so.

Glazebrooke and Williams JJ held that economic benefit remained relevant to the analysis of a reasonable time for remediation of harm. While the Chief Justice was of the view economic benefit had no relevance to the material harm assessment, her honour was content to adopt the approach of Glazebrook and Williams JJ to reach a majority.

Young and Ellen France JJ did not consider the legislation imposed a bottom line, though acknowledged environmental factors were likely to carry greater weight than other considerations.

Failure to favour caution and environmental protection

The Court unanimously held the DMC made an error of law by failing to favour caution and environmental protection as required by the EEZ Act. A diverse range of seabirds and marine mammals reside in the South Taranaki region, and the extent to which the animals would be affected by TTR’s operations was unclear. Due to the uncertainty of the information, the DMC could not be satisfied the harm would be mitigated or avoided by their imposed conditions.

Treaty of Waitangi

Section 12 of the EEZ Act imposes a responsibility on the Crown to give effect to the principles of the Treaty of Waitangi. The Supreme Court agreed the ability of statutory decision makers to respect Treaty principles should not be limited unless the intention is made clear. In this case, the DMC was required to consider the effects of activities on existing interests, which  included tikanga-based customary rights such as kaitiakitanga. The Court also affirmed tikanga as law, drawing on earlier cases such as Takamore v Clarke, and held it must be considered by the DMC where applicable.

The Court held the DMC had failed to properly engage with Māori interests and the relevant kaitiakitanga principles. Additionally, the DMC should have considered possible future claims by iwi under the Marine and Coastal Area (Takutai Moana) Act 2011. The DMC incorrectly regarded the Treaty principles as merely influencing their analysis, rather than as directly relevant considerations. This was an error of law.


The Supreme Court upheld the High Court decision to quash the consents, and dismissed the appeal. The Court referred the matter back to the DMC for reconsideration. Glazebrook J disagreed with the majority that the matter should be reconsidered, as the consent application should have been declined based on available information.

For further information, please contact Director Brigitte Morten

Franks Ogilvie acts Trans-Tasman Resources Limited, but did not represent them in this proceedings nor the DMC process.

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