The election of either Mr Ruairi Quinn or Mr Brendan Howlin as the Labour Party's eighth leader today is expected to be decided by just a handful of votes. The voting difference between the two will not, however, be revealed when the winner is announced.
By lunch time, the party will have its new leader in place following a week-long campaign that appears to have left party unity intact.
Following the secret ballot in party rooms at 11 a.m. the new leader will set out his priorities for the re-invigoration of Labour at a press conference in the National Gallery.
Up to last night sources in both camps insisted they were on course for victory, albeit by an extremely narrow margin.
Exuding confidence, Mr Quinn's supporters were yesterday claiming that he had already secured 38 definite commitments of support from the 64-member electorate.
The winning candidate needs 33 votes to secure overall victory.
As the two-horse race entered its final phase, the Quinn campaign was boosted during the day when Senator Kathleen O'Meara of North Tipperary confirmed publicly that she would be supporting the former minister for finance. Her declaration broke the Dublin-rural bogy that was, up to then, working in favour of Mr Howlin.
Until yesterday, Mr Quinn did not appear to have the support of any non-Dublin members of the PLP. As voting drew near, it seemed that the PLP was breaking down almost 50-50 behind each candidate.
"The campaign has been tense, understandably - the prize is very substantial. But it has been, in my estimation and I believe the estimation of my colleague, Brendan Howlin, conducted in a very responsible manner. Whatever the result, it augurs very well for the party," Mr Quinn said.
Sources close to Mr Howlin said two more of the critical "undecided" voters had informed them of their intention to support their candidate today.
Mr Howlin told The Irish Times that, while the result would be very close, he believed he will emerge as winner.
"I will have the edge. This contest is extraordinary in its closeness but we have shown good internal discipline. We set out to ensure that we would cause no fractures in the party," he said.