The Maori Party is threatening to pull its support for the Government over partial asset sales.
The party is concerned the Government will leave out Treaty of Waitangi provisions in legislation that will pave the way for the partial sale of four state-owned enterprises (SOES) assets.
It says section nine of the State-Owned Enterprises Act, which says the Crown must act in a manner that is consistent with the Treaty, should be included in any new legislation.
In order for such partial sales to proceed, the SOEs in question must first be removed from the Act and then included in new legislation.
Maori Party co-leader Tariana Turia says if section nine is removed, the Government will not have to consult with Maori.
The Maori Party supports National on confidence and supply, but Mrs Turia says the issue could be a deal breaker.
She says the party will take guidance from its constituents, as well as iwi leaders.
And Mrs Turia says the party will be vigilant and, if it comes down to the wire, will consider its position with the Government.
Her co-leader, Dr Pita Sharples later told Checkpoint that if the party's constituents tell it to walk away from its relationship with the National Party, it will do so.
He said the party was getting bombarded with calls about the matter.
Questions raised about Government stability
A Radio New Zealand political reporter says, even without the Maori Party, the Government has a one-seat majority.
However, the Labour Party says the threat by the Maori Party to pull its support brings the stability of the National-led government into question.
Leader David Shearer says the Prime Minister electioneered on the fact that his was going to be a stable government, but within a month of it coming into operation it was already seen as unstable.
"It's very much reliant now, if the Maori party did walk away, on ACT," he says.
The Prime Minister says he is confident the Maori Party will remain part of the Government.
Mr Key says the Government is open-minded about finding a solution, and there is a lot of discussion to be had, including with the Maori Party.
He says the Government is totally committed to its treaty obligations.
Meanwhile, New Zealand First says it is disgraceful that the Maori Party is raising concerns about Treaty rights in State asset sales two months after the election.
Leader Winston Peters says the Maori Party should have raised the issue while it was negotiating its support deal with National.
A series of hui is being held around the country in February as the Government consults iwi about the legislative changes and the Maori Party has encouraged iwi to defend their Treaty rights at the meeting.
A discussion document will be released on Wednesday ahead of the hui but Mrs Turia says she is not impressed with the timing of the document so close to Waitangi Day.