A by-election in former prime minister Malcolm Turnbull's seat of Wentworth will be held on October 20 — the first vote since the Government's chaotic leadership spill.
The vote was triggered after Mr Turnbull resigned from the Parliament following the Liberal leadership spill that saw him lose the prime ministership.
Labor's candidate Tim Murray has already been campaigning, while the Liberal pre-selection — which eight people are expected to contest — will be held on Thursday night.
The seat is held by the Liberals on a 17.7 per cent margin, but ABC election analyst Antony Green has said next month's vote could be a lot closer.
The vote looms as a major electoral test for the Government, after its chaotic leadership spill in which Scott Morrison was given the nation's top job.
Andrew Bragg, who was widely considered the frontrunner for Liberal pre-selection, on Monday announced he was pulling out of the race.
He said the party should pick a woman for the seat.
There are three women who have nominated — former Government staffer and businesswoman Katherine O'Regan, former Turnbull staffer and Woollahra councillor Mary-Lou Javis and rheumatologist Maxine Szramka.
City of Sydney councillor Christine Forster, the sister of former prime minister Tony Abbott, put her hand up and then changed her mind saying her candidacy was proving "divisive".
Former Wentworth member Peter King is among the eight nominees, while the former Australian ambassador to Israel Dave Sharma is another high-profile candidate.
The other candidates include Richard Shields, Michael Feneley and Carrington Brigham.
The Greens have nominated Dominic Wy Kanak but the biggest threat to the Liberals is expected to come from Dr Kerryn Phelps — another City of Sydney councillor — who could run as an independent.
