Iwi, environmentalists and fisheries groups will mount a final defence against seabed mining in South Taranaki at the Supreme Court on Tuesday.
Offshore mining company Trans-Tasman Resources is appealing earlier decisions by the High Court and the Court of Appeal against the project.
If granted, the consent could allow ironsand mining for 35 years.
Its opponents say the project will irreversibly damage an ecosystem that is home to dolphins and whales.
Debbie Ngarewa-Packer is the kaiarataki of Te Rūnanga o Ngāti Ruanui and co-leader of the Māori Party.
