Fianna Fáil will select its candidate to run in the Kildare North by-election next month at a convention vote at the Glenroyal Hotel in Maynooth tonight.
Candidates in the race are Cllr Michael Fitzpatrick, Ms Áine Brady, Cllr Liam Doyle, Mr Anthony Creevy, and Cllr Willie Callaghan.
Up to to 300 people are due to attend the convention to be chaired by the Minister for Finance, Mr Cowen.
The vote is expected to be tight, with Cllr Michael Fitzpatrick and Ms Áine Brady seen as the strongest candidates.
Cllr Fitzpatrick has run the constituency operation of former finance minister Mr Charlie McCreevy and Ms Brady is the sister of the Government Chief Whip, Mr Tom Kitt, and Galway East TD, Mr Michael Kitt.
The candidates for the other parties in the by-election are Fine Gael's, Mr Darren Scully; Progressive Democrat Senator Ms Kate Walsh; Green Party Councillor J.J. Power; and the Independent Leixlip-based councillor, Ms Catherine Murphy.
