Barnaby Joyce has resigned as Deputy Prime Minister and Nationals leader after facing sustained pressure to quit following revelations of his affair with a former staffer.

Key points: Barnaby Joyce will resign as Deputy PM and Nationals leader at a party meeting on Monday

Barnaby Joyce will resign as Deputy PM and Nationals leader at a party meeting on Monday Mr Joyce says he's standing aside to protect his new partner and family

Mr Joyce says he's standing aside to protect his new partner and family Prime Minister Malcolm Turnbull thanked Mr Joyce for his service

In a separate matter, Mr Joyce is also the subject of a sexual harassment claim received by the Nationals.

Mr Joyce explained his decision to quit the frontbench, saying there had to be some "clear air".

He said he would resign at a meeting of the Nationals in Canberra on Monday morning.

Mr Joyce said he would sit on the backbench and would not be resigning from Parliament.

He informed acting Prime Minister Mathias Cormann of his decision to stand down on Friday.

Mr Joyce has not said who should replace him as leader and deputy prime minister, but Veterans Affairs Minister Michael McCormack is the leading contender.

Reflecting on his leadership, Mr Joyce said it had been an incredible privilege to have been deputy prime minister.

But he said he had faced a litany of allegations, although he believed none of them had been sustained.

He acknowledged the controversy had left him with little choice.

"It is quite evident that you can't go to the dispatch box while issues like that are surrounding you," Mr Joyce told reporters in Armidale in his electorate of New England.

He thanked the people of his electorate and said people were backing him even though he suspected some of them did not vote for him.

"People literally running up and someone crying, offering their support to me," Mr Joyce said.

"I don't deserve the support that you have given me.

"At the end, no not hard at all," he said of his dramatic decision to walk away from his powerful roles.

Sorry, this video has expired Recap the moments that defined Barnaby Joyce's political career to date.

Turnbull reacts to Joyce's decision

Prime Minister Malcolm Turnbull issued a brief statement thanking Mr Joyce for his service, describing him as a "fierce advocate for rural and regional Australia".

Mr Turnbull said the Coalition between the Liberals and the Nationals remains "undiminished".

The Prime Minister is in the United States, but had made it clear in the past week that he was angry with Mr Joyce.

Mr Joyce emphasised that standing down was aimed at protecting his new partner who is due to have their baby in April, as well as his estranged wife and daughters.

He said his resignation as leader would act as a circuit breaker. "It has got to stop. This has got to stop and it is not fair on them," he said.

Media coverage has been intense with national newspapers running the story prominently for well over a week.

Mr Joyce described the reporting as completely and utterly unwarranted, but found some humour in the situation.

He said the controversy also had to end for the sake of the "poor buggers who are parked outside my house every day", referring to the lurking media.

He said the media should not expose private relationships in the way it had scrutinised his.

Sorry, this video has expired On February 15, Malcolm Turnbull delivered a scathing assessment of Barnaby Joyce's behaviour

He apologised to his pregnant partner Vikki Campion, who was photographed on the front page of the Daily Telegraph newspaper earlier this month.

"The idea that for Vikki, walking across the road as a pregnant lady and just being put under so much pressure, I thought that is not who we are in Australia," he said.

"That's not the kind of people we are. I am the public figure — go after me. That is what I get paid for.

"But don't go after private individuals. It is just wrong."

Nationals look to future

Veterans Affairs Minister Michael McCormack has confirmed he is standing for the leadership.

"I am a fighter and I have the drive to deliver," Mr McCormack said.

Nationals backbencher Mark Coulton said Mr Joyce had done the right thing by resigning.

Mr Coulton said he would back Mr McCormack as leader.

Former Cabinet Minister Darren Chester announced he too would back Mr McCormack and ruled out making a bid himself.

He said Mr McCormack had the passion, enthusiasm and determination to deliver for all regional Australians.

Another backbencher, Ken O'Dowd, praised both Mr McCormack and David Gillespie as potential leaders.

Dr Gillespie has confirmed he will also contest the leadership.

He is the Assistant Minister for Children and Families and has been in parliament since 2013.

Federal National Party president Larry Anthony praised Mr Joyce as a great leader and a true champion of regional and rural Australia.

"The party will greet this news with a heavy heart but we understand and respect his decision to stand down as leader," Mr Anthony said.

"The Nationals' thoughts and support are with Barnaby and those closest to him at this time."