The Cabinet has yet to decide whether New Zealand should reverse its stance and endorse the UN Declaration on the Rights of Indigenous Peoples, despite Maori Affairs Minister Pita Sharples saying an announcement is imminent.

The Maori Party co-leader - a minister outside Cabinet - yesterday said the Government would sign the declaration within a month.

That timing was later contradicted by Prime Minister John Key, who said Cabinet ministers had yet to see official advice on the matter.

Mr Key described New Zealand's position as "a work in progress".

"I think it's fair to say progress is being made," he told reporters accompanying him on his four-day, four-country South Pacific trip.

"We've been working our way through that just to make sure we've got all the i's dotted and t's crossed. I'm feeling more confident that we can sign the declaration but I wouldn't want to put a time frame on it."

The UN declaration was approved in 2007 following backing from 143 member states. New Zealand was one of four countries which voted against the text. The others were Australia, Canada and the United States.

The declaration is not binding, but the then Labour administration would not support something which it said implied different classes of citizenship.

New Zealand's permanent UN representative, Rosemary Banks, cited the declaration's provision on lands and resources as reason why it could not be implemented in New Zealand.

Article 26 states that indigenous peoples have a right to own, use, develop or control lands and territories that they have traditionally owned, occupied or used.

"For New Zealand, the entire country is potentially caught within the scope of the article. The article appears to require recognition of rights to lands now lawfully owned by other citizens, both indigenous and non-indigenous." While the declaration was explained by its supporters as being an aspirational document - intended to inspire rather than to have legal effect - New Zealand did not accept that a state could responsibly take such a stance.

Mr Key said Dr Sharples was a strong advocate of New Zealand following Australia's recent decision to reverse its position.

"Australia signed up some months ago, and he's keen to see New Zealand make progress. We understand that. There's one or two issues we're wanting to work through. It's an aspirational goal.

"It's not a binding document which supersedes New Zealand law. But I think it's important to understand fully any implications for New Zealand outside of that."

Dr Sharples, who is travelling with the Prime Minister, said New Zealand's endorsement was "going to happen very soon" and he expected to make a joint announcement with Mr Key upon their return.

Some "polish" still had to be put on the statements and the conditions.

Labour leader Phil Goff said National was merely trying to keep its support partner happy, but had no intention of implementing the declaration's contents.