Nationals leader David Littleproud has unexpectedly quit his post, declaring he is “buggered” and “out on my feet”.

His announcement came as a shock to colleagues and follows a period of extreme turbulence for his party and the Coalition, which split twice during this term.

Littleproud has been a controversial and, in terms of Coalition relations, provocative, leader. Although the Nationals held their lower house seats at the election, since then two of their high profile MPs have defected. Jacinta Nampijinpa Price went to the Liberals immediately after the election, and former deputy prime minister Barnaby Joyce jumped to One Nation.

A dramatic surge in the support for One Nation in recent months has put Littleproud under intense pressure to try to combat that party’s increasing attraction to many voters who formerly supported the Nationals.

Littleproud had a bad relationship with former Liberal leader Sussan Ley and triggered both fractures between the two parties.

He has been much closer to the new Liberal leader, Angus Taylor, under whom relations between the parties have so far been smooth.

The Nationals will meet at 10am Wednesday to replace Littleproud. They need to do so quickly, as they have a candidate running in the May 9 byelection in Ley’s former seat of Farrer. On early indications, the Nationals have almost no chance of winning the seat, which former deputy prime minister Tim Fischer held for them before Ley.

Nationals senator Ross Cadell told Sky News the leadership contenders could be deputy leader Kevin Hogan, former leader Michael McCormack, who served as deputy prime minister, outspoken backbencher Matt Canavan and Senate leader Bridget McKenzie. Littleproud did not endorse a successor.

Later Hogan said in a statement: “After being approached by a number of my colleagues, I have formally put my hand up for the Leadership position.”

Canavan said he would run. “I believe I have the best chance to help win the battle for an Australia first plan that can deliver a better life for all Australians.”

Sources confirmed McKenzie was likely to stand.

Littleproud, who did not announce his plan at the Nationals’ regular party meeting on Tuesday, held a news conference after question time with his wife Amelia at his side.

He said he would stay on in his regional Queensland seat of Maranoa, including re-contesting it at the next election. He left open the possibility of serving on the shadow frontbench.

Despite internal and external criticism of his performance, Littleproud’s leadership position did not appear to be under any threat. One of his techniques for retaining support was to take every decision, however small, to the party room.

At his news conference, he defended his record saying, “I am proud of us recapturing our identity, for who we are and what we stand for. For that 30% of Australians who live outside a capital city.”

He said he had done this with the Voice (when the Nationals preempted the Liberals with their opposition) and on other policy areas, including net zero. “It’s not probably since John McEwen has the National Party leader had to stand up and show the courage of their character and […] stand for what their party room wants them to stand for. So I’m proud but I’m tired.”

“It is time for me to feel normal again, it has been a pretty rough road since the election.”

Littleproud was highly critical when asked about working with Ley. He said it was a mistake after the election to “wipe all our policies because all we did was leave a vacuum for someone to walk into.

"I stood and fought for those four policies that meant so much for our party room. […] I wasn’t going to let them go.

"And then [after the Nationals defied shadow cabinet solidarity] I was not going to stand by while my mates got punted for not doing anything wrong.

"Where I come from, if one of your mob gets knocked over and it is not for the right reason, you come swinging back. That is how we operate. The culture of National Party has always been like that. I am proud of that.”

Littleproud said to go on as leader “would be the wrong thing for me to do. I love the National Party. I grew up in it, I’ll bleed, to the day I die, green and gold, I love it, and it’d be wrong for me to say that I’m the right person to continue to lead. That’s tough for me to say, [that] I think someone better can do it, because I don’t have the energy. I’m out of my feet. I’m done.”

Barnaby Joyce, who said Littleproud’s ostracising of him was one reason for defecting, blasted Littleproud. He told The Australian: “Mr Littleproud has to accept responsibility for the existential crisis he left the National Party in.

"When I heard he said he was proud of what he achieved and compared himself to Black Jack [John] McEwen, I didn’t know whether that was pathos or AI interfering with my news.

"We had senior people leave such as David Gillespie, Keith Pitt, Jacinta Nampijinpa Price. We had a [Senate] seat that was lost, which was Perin Davey. Two people who basically walked out in myself and Andrew Gee, and Jacinta.”

Taylor described Littleproud as a “committed Coalitionist”.

Nationals federal president Andrew Fraser said: “I congratulate David on his personal strength and conviction that saw The Nationals lead the debate on the Voice and on the development and adoption of an energy and climate policy that will meet our future energy needs and allow Australian businesses to thrive.

"We are not a faction of the Liberal Party; we have a partnership, and David’s leadership never let them forget it.”