The Prime Minister has indicated Associate Maori Affairs Minister Tariana Turia will lose her ministerial portfolios if she votes against foreshore and seabed legislation.
Helen Clark said last week that Cabinet would consider the proposals today though public announcements on any decisions are unlikely immediately.
The Prime Minister has given Mrs Turia permission to voice dissent and abstain from voting.
However, in a meeting with directors of Maori health boards in Wellington last week Mrs Turia gave the impression she was thinking about going further.
Her options include voting against the legislation or even quitting Labour and Parliament.
Mrs Turia's name has also been linked with the possible formation of a new Maori party.
Mrs Turia is the MP for Te Tai Hauaru and holds ministerial posts outside Cabinet.
Helen Clark told the Dominion Post that Mrs Turia was well aware that voting against the bill was more serious than abstaining.
Asked if it would require her to give up her ministerial warrants, she replied: "That's the conclusion most people would draw."
In March, Mrs Turia said she had ruled out resigning from either the party, her ministerial portfolios, or Parliament.
She and other Maori MPs have been under immense pressure because of vocal opposition among many Maori to the proposals.
Asked last week whether Mrs Turia still ruled out resigning from the party, or her portfolios her spokesman said he had no comment.
Mrs Turia has said "not a single iwi" in her electorate favoured the foreshore and seabed proposals.
A national hui this month called on all Labour Maori MPs to cross the floor and vote against the introduction of foreshore legislation.
Another Maori MP Nanaia Mahuta is keeping her options open.
Helen Clark said last week she believed most of her Maori MPs would support the legislation, as ministers came close to finalising policy details.
The Government this month said it was considering combining the concepts of Crown ownership and public domain for the foreshore and seabed.
Helen Clark today told Newstalk ZB radio she did not know what Mrs Turia's current position was.
"I don't know what her current thinking is but I don't have any update on the intention to abstain."
Asked what would happen if Mrs Turia crossed the floor, Miss Clark said: "Well, that will cause her considerable difficulties."
It was "almost certainly the case" that she would lose her ministerial warrants if she did that.