Unsuccessful Gilmore candidate Neil Reilly will nominate for the casual Senate vacancy created if former foreign minister Bob Carr retires from Parliament.
"If Carr retires, which is on the cards, that will create a casual Senate vacancy and the Sussex Street powers-that-be look like they'll shoehorn Paul Howes in," Mr Reilly said.
"If someone else nominates they'll have to have a vote. I thought I'd force that process."
Mr Reilly, who previously said he would call time on his parliamentary aspirations after losing to Liberal Ann Sudmalis, announced his intention to contest the Senate vacancy on Facebook yesterday. He said his move was part of the reform process initiated by Kevin Rudd, but conceded his chances of success were unlikely.