Mr Michael Noonan is expected to be elected leader of Fine Gael this afternoon and to drop at least seven senior party figures from his first front bench, to be announced by Tuesday.
While Mr Enda Kenny's supporters insisted last night that victory was still possible, Mr Noonan was believed to have more than 30 committed voters and could end up with more than 40 votes. Senior party member Mr Sean Barrett declared last night that he would support Mr Kenny.
There is speculation that today's vote may be a run-off between Mr Noonan and Mr Kenny after Mr Bernard Allen announced last night he was dropping out of the contest. Speculation now centres on the intentions of Mr Jim Mitchell, who would not say last night what he intended to do.
Earlier, he met Mr Noonan to discuss strategy on the eve of the meeting of the party's 72 deputies, senators and MEPs which will decide who will lead the party into the next general election. However he would not comment on whether his name would be on the ballot paper.
Mr Allen conceded he did not have enough support to seriously challenge for the leadership. While he has just three publicly declared supporters, including himself, he maintained his vote would have been "on the verge of double digits".
He declared he would be voting for Mr Kenny. Mr Noonan now has 23 declared supporters, with 12 for Mr Kenny and five for Mr Mitchell. However, just under half of the parliamentary party - 32 members - have yet to declare their allegiance publicly. It is these votes that will decide the outcome, although a wide range of sources in the party yesterday predicted Mr Noonan would receive the required 37.
Should he be successful, Mr Noonan is expected to spend the weekend and Monday consulting colleagues before finalising his new front bench. The team of senior spokespersons is expected to be smaller than the 23member front bench appointed by Mr Bruton, with seven or more senior figures at risk of losing their positions.
Those tipped for promotion include Mr Noonan's campaign manager Mr Paul Bradford and Dublin South TD Ms Olivia Mitchell, who publicly backed the heave against Mr Bruton in two important interviews.
With the front bench expected to be slimmed down there will be more demotions than promotions. However, in a move to unite the party he is expected to retain some of those who were seen as loyal to Mr John Bruton, including the former leader's brother Mr Richard Bruton, party whip Mr Charles Flanagan and social welfare spokeswoman Ms Frances Fitzgerald. However, their responsibilities may be changed.
There is speculation that the Fine Gael leader in the Seanad, Mr Maurice Manning, the leader of the party's MEPs, Ms Avril Doyle, and party chairman, Mr Phil Hogan, may retain their roles but no longer sit on the front bench.
Others whose positions may be in doubt under a Noonan leadership include deputy leader Ms Nora Owen, Mr Gay Mitchell, Mr Bernard Allen and Mr Paul Connaughton.
Mr Mitchell would not comment last night on speculation that he would withdraw from the contest. A number of Dublin members of the parliamentary party who support either Mr Noonan or Mr Kenny intend to give Mr Mitchell their first preference vote.
This, according to one, is a tactical vote designed to ensure that the Dublin "voice" within the party is recognised.
Today's meeting begins at Leinster House at 11 a.m. and is expected to last up to three hours. The result of the vote is expected to be announced shortly before 2 p.m., with the new leader giving a press conference in Dublin's Mansion House an hour later.