Political support for the Kermadec marine sanctuary hangs in the balance after Labour and the Greens both suggested they won't support it if the Government doesn't get iwi support.

The opposition parties voted in support of the bill.

But now the legislation has been delayed while the Government negotiates with the Maori Party and Te Ohu Kaimoana over the 620,000 square kilometre sanctuary.

The Maori Party says it's a breach of Maori property rights and has threatened to walk away from its confidence and supply agreement.

Greens co-leader Metiria Turei says the party "reserves all rights" in terms of how it votes.

"We're very disappointed the Government has made such a mess of the sanctuary process and is delaying it until the negotiations are done," Ms Turei says.

"We certainly don't support breaches of the Treaty and it's clear there's been a breach of the process in working with iwi Maori on the Kermadecs, the Government could have done a better job.

"There is no choice, the question is we want to make sure there is marine protection in the EEZ and the Kermadec Sanctuary goes ahead, and the only way we can be sure of that is when there is iwi support. We want both and believe both is possible."

Earlier, Labour leader Andrew Little made it clear his party would only decide how it would vote once negotiations between the Government and the Maori Party had reached a conclusion.

Ms Turei says: "The Government has left the whole country in a mess. Nick Smith has made a terrible hash of this incredible opportunity for the sanctuary."

Asked why the Greens took so long to realise there was a potential Treaty issue, Ms Turei said the process problems had become more apparent in the last few weeks.

Environment Minister Nick Smith won't take part in the negotiations between the Maori Party and the Government – Bill English will instead do that job.

Maori Party co-leader Marama Fox says it's pleasing the Government is "finally" listening to Maori on the issue.

Nick Smith Source: 1 NEWS