EUROPEAN Affairs Minister Lucinda Creighton says she is not prepared to "suck up bad law and a breach of principle" over the abortion legislation.
She also said there should be a free vote on the issues of conscience like abortion, and rejected the idea that the whip was there to protect TDs from aggressive lobbying.
Ms Creighton said TDs should be able to "stand over our values and stand over our principles" and she has no interest in hiding behind any whip.
"This idea that we should be cosseted or protected from the electorate is bizarre and I disagree profoundly."
Ms Creighton is still pushing for changes to the bill, particularly "pathway to care" for pregnant women who are suicidal.
She has already asked for the clause allowing suicide as grounds for abortion to be removed, but this will not happen.
And she told 'Today with Pat Kenny' on RTE Radio she "would certainly feel much more comfortable" if a pathway to care was included.
However, she did not say if she could vote for the bill if it was.
"I have a grave, grave difficulty putting on the statute books something that has no basis in evidence at all, whatsoever, as a treatment."
She also said members of her local party in Dublin South East "almost to a man and a woman" advised her to do what she felt was best. Fine Gael members in the constituency say they have told Ms Creighton they may not support her to stand for the party again if she votes against the bill tomorrow night.
But she said she is "still holding out some bit of hope" she may be able to support the Government, but added: "If it is the case that I cannot vote for this legislation then I may well be outside the Fine Gael parliamentary party."
She said Fine Gael is breaking pre-election promises, and acknowledged she may lose the whip.
"That's a price I have to be prepared to pay," she said, but added she would have preferred a free vote on issues of conscience.