The Australian prime minister, Tony Abbott, could be removed from office as early as next week after facing a revolt from within his own party.

A backbench MP from Abbott’s governing Liberal party announced on Friday that he would be moving a motion to have the leadership declared open.



The move followed a series of mis-steps and political blunders by the prime minster, including the decision to award a knighthood to Prince Philip on Australia Day.



Speculation had been growing all week over a possible challenge to Abbott but it was not until Friday afternoon that a member of his own party publicly declared that a change in leadership was necessary.

Luke Simpkins, a Liberal MP from Western Australia, emailed colleagues to announce he would move a motion in the party room calling for a “spill” that would throw open the leadership. It is expected to be seconded by another West Australian MP, Don Randall. The party’s MPs will meet in Canberra early next week when parliament resumes after the summer recess.

Simpkins said the knighthood for Prince Philip was “the final proof of [Abbott’s] disconnection with the people”.

“I think we must bring this to a head and test the support of the leadership in the party room,” he wrote.

Less than two hours later Abbott called a press conference at which he declared he would oppose the motion.

“We are not the Labor party,” Abbott said – referring to the tumult of the previous government, when Julia Gillard forced out the Labor prime minister Kevin Rudd, only to have him seize back power in the third of a series of party-room showdowns.

The motion will have to pass with majority support before the Liberal leadership is declared open. Malcolm Turnbull, the communications minister and the man Abbott replaced as party leader in 2009, is seen as the most likely candidate to defeat the prime minister.

The foreign minister and deputy Liberal leader, Julie Bishop, has also been widely touted as a contender.

But Abbott, speaking at the brief press conference, said Bishop had agreed to support him in trying to stop the leadership vote taking place.

Tony Abbott on the brink: where did it all go wrong? Guardian

“They [the backbench MPs] are perfectly entitled to call for this but the next point to make is that they are asking the party room to vote out the people the electorate voted in, in September 2013,” he said.

“We are not going to repeat the chaos and instability of the Labor years. I have spoken to the deputy leader Julie Bishop and we will stand together in urging the party room to defeat this particular motion.”



But the extent of Bishop’s support was unclear. She issued a heavily qualified statement that highlighted cabinet solidarity as her reason for agreeing with Abbott’s request to oppose the attempt to depose him. “I agreed with prime minister that due to cabinet solidarity and my position as deputy there should be support for current leadership in spill motion,” she said.

Bishop told the media earlier on Friday that she had no advice for colleagues who were considering bringing on a leadership spill, saying they would “take whatever action they see fit”.

Abbott has faced growing unrest in his party over the past six months, sparked by a budget in May that was widely criticised as unfair. The government has struggled to pass key parts of it through parliament.

Abbott tried to “reset” the government’s fortunes at the beginning of 2015 but his leadership came under intense pressure after he decided to knight Prince Philip under the Order of Australia – a long-defunct honour he had controversially reintroduced the previous year.

Prince Philip Photograph: Tim Rooke/Rex

The knighthood decision reinforced perceptions in the party that his judgment was poor. On 31 January an earth-shattering defeat for the Abbott government’s conservative bedfellows the Liberal National party in the Queensland state election unleashed a torrent of discontent with Abbott’s leadership among federal backbench MPs.

Turnbull, an Oxford law graduate, defended the former MI5 agent Peter Wright against the British government’s unsuccessful attempt to suppress the publication of his book Spycatcher.

While Abbott vowed to stare down an attempt to end his prime ministership with Julie Bishop’s support, members of his party pondered how to vote. An opinion poll on Friday evening suggested that a switch of leader to either Malcolm Turnbull or Bishop would bounce the Coalition into an election-winning position.

