Māori fisheries trust Te Ohu Kaimoana is taking legal action against the government's move to establish a massive ocean sanctuary around the Kermadec Islands.
Chairperson Jamie Tuuta said the government had ignored the impact the sanctuary would have on iwi fishing interests.
The bill establishing the sanctuary passed its first reading in Parliament unanimously last week.
The Sealord deal in 1992 gave fishing rights to Māori, and guaranteed that the Crown would involve Māori in statutory decisions.
Mr Tuuta said that had not happened in this case, and the bill said no compensation would be paid as a result of the change.
The trust had filed for proceedings in the High Court in Wellington as a last resort, he said.
Iwi leaders from Ngāti Whatua, Ngātiwai, Ngāpuhi, Hauraki, Ngāti Apa-Ngā Wairiki and Ngāti Toa Rangātira were supporting the action, he added.
Twice the size of New Zealand
The Kermadec Ocean Sanctuary would cover 620,000 square kilometres, about 1000km northeast of the North Island - about twice the size of New Zealand's land area.
It would be off-limits to commercial fishing and aquaculture, recreational fishing and fishing-related tourism, as well as oil and gas mining.
Environment Minister Nick Smith said last week that the sanctuary represented a significant commitment to protecting the ocean environment.
Dr Smith said it would contain about 6 million birds of various species, 35 species of whale and dolphins, three species of turtle and 150 species of fish.
He said today that Te Ohu Kaimoana's argument was theoretical, as it had not done any fishing in the area in more than decade.
"TOKM has chosen to take court action. [We are] disappointed by that," he said.
"We'll be vigorously defending the government's position, and through both processes we remain very committed to seeing this Kermadec Ocean Sanctuary being created."
Dr Smith said Northland iwi Ngāti Kuri and Te Aupouri supported the government's bill.
He said New Zealand had been a world leader in establishing national parks and needed to do the same in regard to its marine areas.
"I think the vast bulk of New Zealanders recognise that our oceans are not well managed globally and that New Zealand needs to step up and set aside areas for protection."
A fishing company said it was relieved the Māori fisheries trust was taking legal action against the government's proposed ocean sanctuary.
Solander Fishing chair Charles Hufflett said the ban was not needed and there was already a ban on sea bed fishing.
"It is in the interest of New Zealand to maintain access to the surface fishing that is fish highly migratory passing through the zone and that has no sustainability issues whatsoever."
Mr Hufflett said the area was already the largest marine protected reserve in the country and the government would be introducing a sanctuary for bragging rights.
The government had planned to have the new sanctuary in place by November.