Senior cabinet minister Christopher Pyne is unable to guarantee Tony Abbott will still be leader next week, only saying he 'hopes'  the Prime Minister still has the numbers in the party room.

Mr Pyne also said he could not rule out a leadership spill next Tuesday when MPs meet for the first time since moves began within the Liberal Party to oust Mr Abbott from office.

Appearing on Nine Today program with Labor frontbencher Anthony Albanese on Friday morning, Mr Pyne was asked if Mr Abbott still has the numbers.

"That's a very inexact science, I hope he does, yes," Mr Pyne said.

"Will he be prime minister next Wednesday?" pressed host Karl Stefanovic.

"Well I certainly hope so," Mr Pyne replied.

Mr Pyne, who described himself as a "strong supporter" of the Prime Minister, is the first cabinet minister to express doubts about the future of Mr Abbott's leadership.

"That's an extraordinary statement from Christopher Pyne who can't confirm that the Prime Minister doesn't have the numbers, that means he doesn't," Mr Albanese said.

"When you start having senior people (who) can't say that the Prime Minister has the numbers then it's over."

Mr Pyne used the TV interview to warn colleagues considering throwing out Mr Abbott.

"I assume that the party room knows that the worst thing we could possibly do is change the leadership right now. We have to support the Prime Minister."

Mr Pyne said he would "certainly" vote for Mr Abbott if if there is any kind of ballot on Tuesday but noted he "can't speak for all of my colleagues in a secret ballot".

Speaking on Sydney radio station 2GB a short time later, Mr Abbott said he was not expecting a spill on Tuesday.

"I'm not expecting it, I'm expecting business as usual," he told host Alan Jones.

"I'm expecting just to get on with business and I'm confident that I have the full support of the cabinet."

Pointedly, however, Mr Abbott did not say that he felt he still carried the full support of the party room.

However, a minister, loyal to Mr Abbott, told Fairfax Media that momentum appeared to be building towards a challenge, which is likely to come to a head at the Tuesday party room meeting.

Those in favour of a change said the most likely new leadership would include Mr Turnbull as prime minister, with Ms Bishop remaining deputy and Foreign Minister, with Social Services Minister Scott Morrison, a favourite of the right, taking the reins of Treasury from Joe Hockey.

- with Heath Aston

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