Opposition Leader Sussan Ley has survived a key party room meeting but is still expected to face a challenge to her job in coming days, as a former Liberal leader joins calls for her most likely replacement to declare his hand.
A scheduled gathering of MPs on Tuesday morning passed without significant incident amid furious speculation opposition defence spokesman Angus Taylor will attempt to depose Ms Ley this week.
Mr Taylor's backers claim he has the numbers to win a spill, but he is yet to resign from the front bench - a critical step before announcing his intention to run as leader.
Conservative powerbroker and Liberal senator Jonno Duniam said Mr Taylor needed to effectively put up or shut up.
"If Angus is interested in ... the leadership then he should say so," senator Duniam told reporters in Canberra on Tuesday morning.
"That's something he needs to make clear.
"Then what events take place after that well-trodden path? That's all a matter for him."
Former Liberal prime minister Malcolm Turnbull echoed Duniam's comments, urging Mr Taylor to "stand up and be counted".
"This is a place where we vote in public right?" Mr Turnbull told reporters at Parliament House.
"If Angus wants to be leader of the Liberal Party, he should stand up and say so and say why."
When asked if Mr Taylor was fit to be Liberal leader, Mr Turnbull also gave a less-than-ringing endorsement of his former colleague.
"He is absolutely fit to be leader, because the only qualification for being leader of the opposition is to be a member of the House of Representatives," he said.
Mr Taylor is widely expected to attempt a leadership challenge by Friday, after a string of dire polls showed plummeting voter support for the coalition.
Senators are mostly stuck in parliamentary committee hearings until Thursday afternoon, making a special party room meeting on Thursday evening or Friday the most likely scenario to bring the issue to a head.
During Tuesday's regular meeting, moderate senator Jane Hume asked Ms Ley how she would tackle the grim poll numbers.
Ms Ley replied that unity was important and "disunity is death", according to a party room source.
Senator Hume is being floated as a potential deputy to Mr Taylor, with other Liberal women including Zoe McKenzie and Melissa McIntosh in the mix.
Opposition energy spokesman Dan Tehan and deputy Ted O'Brien are also being discussed in Liberal circles.
But pollster Kos Samaras, a former Victorian Labor strategist, has warned a change of leader will likely not be enough to arrest the coalition's slide in support.
"The antidote to their problems is not the leader," the Redbridge Group director and former Victorian Labor strategist told AAP.
"It would be good policy, and that's a long road ahead of them and isn't an easy solution."
The latest Newspoll for The Australian, conducted during the most recent break-up between the Liberals and Nationals, puts the coalition's first-preference vote at just 18 per cent, eclipsed by One Nation on 27 per cent.
Mr Samaras doubted the coalition could develop robust policies before the next election while competing with the rival conservative party.
"They are not only declining in support in regional Australia to One Nation - they've historically been losing ground to the Labor Party and to independents," he said.
