Malcolm Turnbull has described Tony Abbott's decision to bring the spill motion for the Liberal leadership forward as a "captain's call", while sending the clearest signal yet he would stand for the Liberal leadership if it is declared vacant.

The Communications Minister said on Sunday morning that "anyone" could stand for the leadership – without being disloyal – if a move to spill the Liberal leadership succeeded.

Liberal MPs Arthur Sinodinos and Teresa Gambaro have also lashed the decision, which Mr Abbott announced on Sunday morning, a day after the Prime Minister said the vote would be on Tuesday.

Asked if he had decided whether to contest a vacant leadership, Mr Turnbull said "that's a hypothetical question for the time being".

"The Prime Minister's decision had been, as he said, to hold the meeting on Tuesday and I did praise him for that this morning. Look, he's the Prime minister, he's made a captain's call. He's changed the date of the meeting," he told reporters outside a fundraising event in Sydney.

"If for whatever reason the leadership of a political party is vacant then any member of the party can stand, whether they be a minister or a backbencher, without any disloyalty to the person whose leadership has been declared vacant.

"I'm talking to my colleagues. I know other senior members of the party are doing that. They're the people I want to talk with."

In his National Press Club speech last Monday, Mr Abbott effectively apologised to MPs disgruntled by his so-called "captain's calls", including the paid parental leave scheme and the knighthood for Prince Philip.

Asked if Mr Abbott had shown disrespect by bringing the meeting forward, Mr Turnbull said: "No. The Prime Minister's decision had been, as he said, to hold the meeting on Tuesday and I did praise him for that this morning."

Early vote provides certainty for party: Cormann

But other Liberal MPs, including Finance Minister Mathias Cormann, backed the Prime Minister's decision to bring forward the spill motion to Monday.

Senator Cormann told the ABC's Insiders program the move "provides a certainty for the party and for the country. My colleagues are all professionals. This issue has been discussed among colleagues for some time now".

"I believe that my colleagues know what it is that they are wanting to do. I believe that overwhelmingly my colleagues will support the leadership team that took us successfully to the last election in Tony Abbott and Julie Bishop," he said.

"It's inconceivable that it would be in the best interests of either the Liberal Party or the country for the Prime Minister to go into the Parliament tomorrow with this issue unresolved."

Sinodinos, Stone to vote for a spill

In a stinging rebuke to Mr Abbott, Senator Sinodinos, who served as chief of staff to former prime minister John Howard for a decade, also suggested Foreign Minister Julie Bishop had not been consulted.

Senator Sinodinos, as well as Victorian MP Sharman Stone, on Sunday revealed they would be voting for a spill of the leadership.

"I will vote for a spill as that will help precipitate a discussion," he said.

Senator Sinodinos is well respected in the Coalition and his criticism will carry significant weight in the Liberal party room.

"I am disappointed the party room meeting has been brought forward. MPs should be given adequate time to discuss the matter at hand," he said.

"Tuesday is the time to do that. It is disappointing. Was Julie Bishop consulted about it being brought forward?"

Fairfax Media has been told that Ms Bishop was informed of the decision to switch the meeting from Tuesday to Monday by the Prime Minister on Sunday morning.

'We cannot govern...through belligerence and hubris'

Ms Gambaro on Sunday joined the criticism, speaking out about the current state of the Liberal leadership.

"We cannot govern ourselves in an internal climate of fear and intimidation. And that is the unacceptable situation we have endured for the past five years," she said.

"Equally we cannot govern the country through belligerence and hubris. In our parliamentary democracy, MPs, as elected official, have the individual honour to serve the people of their respective electorates and as such deserve to have their voices heard. This is the path to good government."

Another MP said his Liberal colleagues were outraged by the way Mr Abbott had treated the party room and people opposing the spill were now more likely to vote for it.

However Queensland Liberal senator Ian Macdonald said he backed the change of time, telling the ABC that it was "sensible we start the Parliament with this matter resolved, otherwise the legislative program for Monday and Tuesday is going to be a bit bogged down".

"I don't think there should have been a spill. I think the spill will be defeated," he said.

"He [the Prime Minister] has indicated he's going to change and a whole new approach, I think we should let him do that, see how things go."

Senator Sinodinos' public rebuke of the Prime Minister is the second time in a week he has criticised Mr Abbott.

Last week, Senator Sinodinos, a former Abbott loyalist, described his support for the stricken leader as "ongoing" (but) "not unconditional".

Asked if Mr Abbott would be Prime Minister the next week, Senator Sinodinos replied: "Comrade, ask me next week."

Liberals viewed that intervention as crucial with one calling it "extremely telling".

'I support the PM': Turnbull

Earlier on Sunday before Mr Abbott's announcement, Mr Turnbull praised Mr Abbott for holding the meeting on Tuesday, giving MPs more time to consider their decision and consult with colleagues.

"He's also, I think, shown great respect for the party room by saying that the meeting will be on Tuesday which is the normal party room meeting," Mr Turnbull said outside his Sydney home.

The Communications Minister, who had steered clear of the media and cameras since Mr Abbott agreed to a spill motion upon the request of two WA MPs on Friday afternoon, said MPs needed time to talk among themselves rather than through the media.

Mr Turnbull said as a member of cabinet he was expected to, and would support the Prime Minister by voting against the spill motion.

"I know people keep on saying to me - every day they say 'Do you support the Prime Minister? Do you support the Prime Minister?'. I'm in the cabinet, of course I support the Prime Minister."

Mr Turnbull said many colleagues had asked him what he would do if the spill motion were carried.

"There is certainly a lot of members who have asked me about that, plainly. But it's very important to remember that the leadership of the Liberal Party is, as John Howard said, in the unique gift of the party room. In the unique gift of the party room," he said.

"Now, what that means is that members of the party room have got to have the time to talk to each other, backbenchers talking to each other, backbenchers talking to frontbenchers, frontbenchers talking to frontbenchers and so forth.

"That's the point of Parliament, that people come together and have a talk. That's what we're paid to do by our constituents. It's really important that we talk to our colleagues directly rather than, you know, giving them advice or lecturing them or trying to communicate with them through the media."

Mr Turnbull said the MPs who were proposing the spill motion were not acting on his behalf, but their concerns needed to be treated seriously.

"This is a grass-roots issue that has been raised. That's got to be respected," he said.