Ousted prime minister Malcolm Turnbull has announced he will leave federal parliament after 14 years on Friday.
The resignation of Mr Turnbull, who was succeeded by Scott Morrison after a drama-filled week in Canberra last Friday, will trigger a by-election in the Sydney seat of Wentworth.
Mr Turnbull, 63, told supporters at an electorate conference on Monday night that he would leave on Friday.
Early reports suggest the by-election will be held on October 6.
The Liberal Party comfortably holds the blue-ribbon seat, attracting 67.75 per cent of the vote at the 2016 election.
But the move means the coalition will hold only 75 of 149 seats in the House of Representatives for at least two sitting weeks. It will leave the new PM in a precarious position with no majority.
Thank you. It’s been an honour to serve you as PM. pic.twitter.com/fwNqxUJIVG
— Malcolm Turnbull (@TurnbullMalcolm) August 24, 2018
The sister of former leader Tony Abbott, Christine Forster, has already confirmed she will nominate for pre-selection in the prize seat.
Ms Forster, who is a City of Sydney councillor, said she had a strong record of championing Liberal Party values at a local government level.
Former Australian ambassador to Israel, Dave Sharma, is said to be the frontrunner as the Liberal candidate.
NSW MP Alex Greenwich and GP Kerryn Phelps are reportedly considering running as independents.
Waverley deputy Mayor Dominic Wy Kanak has been announced as the Greens candidate, while Tamarama Surf Lifesaving Club president Tim Murray will run as Labor’s candidate.