Australian Prime Minister Tony Abbott's leadership was under growing threat on Friday with an official confirming a leadership ballot next week.

Lawmaker Luke Simpkins said in an email to colleagues 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 later confirmed that the ballots would go ahead at Tuesday's meeting.

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