Two candidates will compete to become the next leader of the Progressive Democratic party.
Senators Fiona O'Malley and Ciaran Cannon declared their nominations ahead of this evening's deadline.
The election will take place next month.
Minister for Health Mary Harney has been acting as party leader since Michael McDowell stood down having failed to retain his seat in the general election.
Party rules were then changed to allow senators, councillors and party members to contest the leadership.
