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Penny Bradfield, Associated Press
In this Sept. 18, 2013 file photo, Australian Prime Minister Tony Abbott, left, leads the first meeting of his full ministry in the Cabinet Room of Parliament House in Canberra, Australia. The fight over conservative Prime Minister Abbott’s leadership broke out into the open on Friday, Feb. 6, 2015, with a member of his party triggering a potential challenge next week.

CANBERRA, Australia — The fight over conservative Australian Prime Minister Tony Abbott's leadership broke out into the open on Friday, with a member of his party triggering a potential challenge next week.

Lawmaker Luke Simpkins said in an email to colleagues that he will move a motion at a ruling Liberal Party meeting on Tuesday calling for Abbott to declare that his job and that of his deputy Julie Bishop are open to a ballot of 102 government lawmakers.

It is not yet clear whether any lawmaker will be nominated to run against Abbott or his foreign minister.

The party's chief whip Philip Ruddock confirmed that the ballots would go ahead if the motion is passed at Tuesday's meeting.

Halfway through his first three-year term as prime minister, Abbott had been under increasing pressure over poor showings in opinion polls.

Public dislike of Abbott is blamed in part for conservative governments suffering big election losses in Victoria state in November and Queensland state in January.

He has also been widely criticized for making Queen Elizabeth II's husband, Prince Philip, an Australian knight on Australia's national day last month.

Simpkins said in an email to party colleagues the knighthood for Prince Philip was "the final proof of a 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.

Bishop and Communication's Minister Malcolm Turnbull have been touted as potential replacements for Abbott.

While both have made public statements of support for Abbott, they can now sound out supporters from within government ranks now that the ballot is officially on the meeting agenda.

Abbott has warned his colleagues against such a challenge. He said Australians had voted out the chaotic and divided center-left Labor Party government in 2013 because it had changed its prime minister twice in four years.

Government lawmaker Andrew Nikolic told colleagues in an email that the challenge was the "ill-disciplined and self-interested behaviors that the Australian people explicitly rejected in 2013."

"Your actions are disappointing and divisive," Nikolic told Simpkins in an email copied to other Liberal lawmakers. "You do not have my support for this."

Government lawmaker Dennis Jensen, who like Simpkins is from Western Australia state, on Tuesday became the first to publicly state he had lost confidence in Abbott.

Colleague Sharman Stone said earlier Friday that the growing leadership crisis needed to be resolved next week when parliament sits for the first time this year.

"If Tony gets through this, we've got to get behind Tony," she said.

"If someone else does, that's our leader and we get behind that person and we diminish the prospect of having Labor back in because that would be totally catastrophic," she said.