Australia's scandal-hit deputy PM resigns

Sydney, Feb 23: Australia's scandal-hit deputy leader Barnaby Joyce announced today he was quitting and moving to the backbench amid claims of sexual harassment and controversy over an affair with a now-pregnant former aide.

Joyce, whose National Party rules alongside Prime Minister Malcolm Turnbull's Liberals, has been front-page news in Australia for two weeks since it emerged he had left his wife of 24 years for his younger former media adviser, who is now expecting their baby boy.

The 50-year-old had insisted he would ride out the storm but his position became untenable today when a sexual harassment complaint against him, which he denies, was lodged with the party.

"I will say on Monday morning at the party room (meeting), I will step down as the leader of the National Party and deputy leader of Australia," Joyce said at a press conference in Armidale, his country New South Wales electorate.

"It's incredibly important that there be a circuit-breaker, not just for the parliament, but more importantly, a circuit-breaker for Vikki (his lover), for my unborn child, my daughters and for Nat (his wife).

"This has got to stop. It's not fair on them. It's just completely and utterly unwarranted, the sort of observation that's happened."

Joyce was due to be the acting prime minister this week with Turnbull meeting US President Donald Trump in Washington, but opted to take leave.

With Foreign Minister Julie Bishop also out of the country, the role has been assumed by Senate leader Mathias Cormann, who said ahead of Joyce's decision that any harassment claim must be taken seriously.

"Any allegation of sexual harassment is a very serious allegation," he told reporters.