Australian Prime Minister Tony Abbott has said he would bring forward a meeting of his ruling party to consider a challenge to his leadership in an effort to halt a destabilising internal revolt.
A member of Mr Abbott's conservative Liberal Party called on Friday for a secret ballot to decide whether to declare the leadership and deputy leadership positions vacant.
The meeting had been scheduled for Tuesday but will now take place tomorrow.
Removing Mr Abbott would need support from more than 51 of the 102 members of the federal Liberal Party at the party-room vote.
If Mr Abbott is ousted, Australia is faced with having its sixth prime minister in eight years.
"It is important to end the uncertainty at the very beginning of the parliamentary sitting week," Mr Abbott said in a brief statement today.
The prime minister has faced a torrent of criticism in recent weeks over policy decisions ranging from his handling of the economy to awarding an Australian knighthood to Queen Elizabeth's husband, Prince Philip.
Mr Abbott has admitted mistakes as pressure intensified on his leadership in recent weeks.
He vowed to be more "collegial" and "consultative" in his approach.
No member of the government has so far indicated a direct challenge to Mr Abbott.
However, most attention has focused on Communications Minister Malcolm Turnbull, a former party leader toppled by Mr Abbott.
Mr Turnbull, a millionaire lawyer and former investment banker, has not yet said he will challenge Mr Abbott directly but today he gave the strongest indication yet he would run.
"If for whatever reason, the leadership of a political party is vacant, then any member of the party can stand ... without any disloyalty to the person whose leadership has been declared vacant," Mr Turnbull told reporters outside a function in Sydney.
Political analysts said Mr Abbott's move to bring forward the vote on his leadership would give any challenger less time to accumulate support from colleagues, who will return to the nation's capital, Canberra, for parliament tomorrow.
Opinion polls have consistently shown voters prefer Mr Turnbull to lead the party but his views on a carbon trading scheme, marriage equality and support for an Australian republic have made him unpopular with the right wing of his party.