The National Urban Māori Authority (NUMA) is threatening legal action to stop what it calls "iwi fundamentalism at its worst" in a fight to retain control of a $20 million fishing fund.
The authority is a national collective for urban Māori authorities, which aim to support tāngata whenua who don't necessarily know to which iwi they belong.
NUMA chair Willie Jackson said the authority was appalled at a recommendation, made by a sub-committee of Māori fisheries body Te Ohu Kaimoana, that iwi take control of the fund.
As part of a meeting of Te Ohu Kaimoana in Wellington today, there was a unanimous vote by iwi to increase the number of directors of the urban fishing fund - Te Putea Whakatupu Trust - from three to five.
"There is a struggle going on because we'll have no choice but to take them to court... There was a clear view they were going to shut us out and that was what was exhibited in the vote," Mr Jackson said.
He said what iwi leaders were trying to do was disgraceful.
"It's like we don't exist, actually. We just had a vote from them saying that they wouldn't support our motion in terms of us controlling the putea, or money, which is typical from them.
"They've taken 95 percent of the settlement and they can't even let us control a small amount of money that was agreed on some years ago. It's a real disappointment and I think they can hang their heads in shame actually."
Mr Jackson said the trust wanted to wrest control away from urban Māori and create a pan-iwi entity.
He said they wanted to ignore recommendations laid down by barrister Tim Castles, who conducted an independent review of Te Ohu Kaimoana.
"Tim Castles is basically saying this should be left to the urban groups to manage, but they're saying, no, they want to take control of it still.
"What we're saying is [John] Tamihere and I went to Parliament with a mandate from our people to fight for urban Māori rights. The urban putea trust was set up in Parliament and we just want that honoured."
Mr Jackson said he did agree with some of other recommendations made in Mr Castles' review.
"We're on the same path, but we're adamant that our organisation and the urban Māori organisation authority should be the organisation that appoints representatives [to Te Putea Whakatupu Trust]."
He said there was about $540 million in assets allocated for iwi but less than 5 percent was set aside to support the needs of urban Māori.
"We get nothing. We get crumbs at the moment, but we want to be able to access that and control that $20 million," he said.
"They've got to stop this because we fought against them in the '90s and we'll fight again on this if we have to."
Mr Jackson said there was little doubt that NUMA would go to court over the issue, but a final decision would be made over the next few days.