Beleaguered Australian Prime Minister Tony Abbott is to face a leadership vote after Liberal MPs said they would call a challenge next week.
Luke Simpkins, who represents Cowan in Western Australia, said it was "time to test the support of the leadership".
Mr Abbott has faced growing questions about his leadership in recent weeks.
He was widely ridiculed for giving a knighthood to Prince Phillip, husband of Queen Elizabeth, and blamed for a Liberal defeat in Queensland elections.
In an email to the party which was carried by Australian media, Mr Simpkins said he had been "inundated" with questions about "the direction the government is being led in".
"The knighthood issue was for many the final proof of a disconnection with the people," he said, adding that it was "time to test the support of the leadership in the party room".
Mr Simpkins said he had no leadership ambitions himself but wanted to ensure "that the economic vandals [of the Labor party] do not get back into power and our children and grandchildren are not left to pay Labor's bill".
"I do this because I believe it is in the best interests of the people of our country."
Analysis: Wendy Frew, Australian Editor
Mr Abbott's leadership had been criticised before but his decision on Australia Day to award a knighthood to Prince Philip was a game-changer.
Now, two backbenchers have come forward to lance what former Victorian Premier and Liberal heavyweight Jeff Kennett has likened to a festering boil of discontent with Mr Abbott.
The call for a party room spill on Tuesday by MPs Luke Simpkins and Don Randall has set the hares running. MPs are now furiously phoning each other to count the numbers for the pretenders. Short odds are on Communications Minister Malcolm Turnbull and Foreign Minister Julie Bishop.
Ms Bishop's unsuccessful stint as shadow treasurer is seen as her main stumbling block. Mr Turnbull's progressive views and support for emissions trading have made him very unpopular with National MPs in the Liberal-National coalition.
Leadership spills have failed in the past, however, and Mr Abbott could still survive to see another day.
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Profile: Malcolm Turnbull
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Liberal chief whip Philip Ruddock confirmed that the motion - which is being seconded by Don Randall - would be discussed at a party meeting on Tuesday.
MPs will first vote on whether to allow the leadership spill to go ahead. If the motion passes, a leadership vote will take place.
Foreign Minister Julie Bishop, Communications Minister Malcolm Turnbull and Social Services Minister Scott Morrison are seen as possible contenders, though none has so far said they would run against Mr Abbott.
Ms Bishop earlier this week told cabinet she was not seeking to challenge the prime minister. She had spent Thursday, along with Treasurer Joe Hockey and Education Minister Christopher Pyne, playing down spill rumours.
On Friday Ms Bishop she had no comment to make on the motion.
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