The Freshwater Iwi Leadership Group will go back to the Supreme Court if ownership negotiations with the Crown cannot be sorted out, the group's adviser says.
The comments come after Prime Minister John Key reiterated yesterday that no one can own the resource, though the Government would keep working with iwi over rights.
Freshwater rights came to the fore after the failure in 2013 of the Maori Council and other claimants' legal attempts to stop the partial sale of Mighty River Power.
The Freshwater Iwi Leadership Group maintains the Waitangi Tribunal decided iwi rights and interests in water were akin to ownership, and it wants to reconcile that in today's terms, despite the Government questioning that right.
Group adviser Willie Te Aho said the original decision was dismissed provided the Government addressed the issue, and iwi would consider their options if an agreement was not reached.
"To work with the Crown, that is one of the options that we have," he told Morning Report.
"The other option is clearly going back to the Waitangi Tribunal and last but not least working through the Supreme Court."
Mr Te Aho said iwi would also consider negotiating with regional councils.
No dedicated allocation rights
Mr Key said yesterday the Government believed no one could own water and it was not about to change its mind.
"There are iwi leaders that believe there should be a national settlement and that they should have dedicated allocation rights, and what I'm saying is that's actually not the Government's position and it doesn't support that.
"It does believe that there should be a mature conversation with all the stakeholders ... but there won't be a national settlement under us and there won't be a change of ownership under us."
Mr Key acknowledged it was a difficult and long-standing issue.
"What we do want to do is make sure that water is available and used across the economy and Maori are but one, important, but nevertheless but one, of a number of stakeholders who have an interest."
Federated Farmers spokesperson Ian Mackenzie said the group was watching negotiations with iwi and the Crown closely.
"You can't settle one grievance to Maori or iwi by creating another grievance by taking away water allocation to the general public of New Zealand."
Mr Mackenzie said Federated Farmers just hoped the Crown maintained its position.
The chairperson of Te Arawa, Toby Curtis, is a member of the Freshwater Iwi Leaders Group.
Sir Toby said progress was being made, but slowly, and it was a matter of being patient.
"On our side of the fence we would like it to go a bit quicker, but however we are moving forward."
Sir Toby said everybody in the country should have access to water.
The last scheduled hui to discuss water rights with iwi will be held on 23 April in Hokitika.