SYDNEY - Former Australian Prime Minister Malcolm Turnbull is expected to quit parliament this week, Australian media reported on Monday (Aug 27).

Mr Turnbull, ousted last week in a party leadership vote, will quit on Friday, the Sydney Morning Herald (SMH) and Australian Broadcasting Corp (ABC) reported. His resignation from the House of Representatives will trigger a by-election in his Sydney electorate of Wentworth.

The government presently has a one-seat majority in parliament.

"I've had a great team in Federal Parliament and a great team here at Wentworth," the former prime minister told a party gathering at Easts Rugby club on Monday night, the SMH reported.

"But as you know, my prime ministership has come to an end. The circumstances have appalled most Australians but again, I won't labour the point."

He told supporters he would resign from the House of Representatives on Friday (Aug 31) and that he would send a letter to his community on Tuesday (Aug 28) to let them know of his decision.

The SMH said it understood the resignation would set up Oct 6 as a potential date for the by-election, amid signs of a ferocious swing against the ruling Liberal party that could put the seat at risk.

But the date of the by-election is out of Turnbull's control because it will be set by the Speaker of the House of Representatives, Tony Smith.

The ABC said Christine Forster - the sister of former prime minister Tony Abbott, who was instrumental in Turnbull's ouster - has confirmed she wants to be the Liberal Party's candidate for the seat.

Forster has been a Liberal councillor for the City of Sydney for the past six years and was a leading figure in last year's successful same-sex marriage campaign.