The Te Ohu Kaimoana Fisheries Trust is taking the Government to court, saying its rights have been overruled, but Environment Minister Nick Smith is dismissing the move.
"I'm not concerned particularly by the court action, and I invite those iwi leaders and others who have a concern or passion about the bill: take the opportunity to make a submission."
He says the suggestion that somehow New Zealand made a decision to create the sanctuary because of international pressure is "nonsense".
Conservationists are concerned about the dispute, and the World Wildlife Fund's Chris Howe says it's a worry.
"We campaigned for the Kermadec region to become an ocean sanctuary where there's no fishing, no mining and no oil extraction. That's what we think would be best for New Zealand."