Senior party figures in Silvio Berlusconi's fractious centre-right party have urged Italian lawmakers to defy the billionaire media tycoon and back Prime Minister Enrico Letta in a confidence motion expected on Wednesday.

Party secretary and Interior Minister Angelino Alfano and Transport Minister Maurizio Lupi, who handed in their resignations on Berlusconi's orders on Saturday, called on the party to back Letta in the vote.

"I remain firmly convinced that our entire party should support Letta in a confidence vote," Alfano told reporters.

Berlusconi's People of Freedom (PDL) party has come close to breaking apart after he pulled his ministers out of the ruling coalition at the weekend and called for new elections.

Italy, the euro zone's third-largest economy, has been in political turmoil for the past week, and even if Letta's government survives the vote, there is no certainty that his administration will be strong enough to enact effective reforms to confront its longest postwar recession.

However, the breakdown of unity in Berlusconi's party is a watershed moment for the man who has been the undisputed leader of Italy's centre-right for two decades and opens an unpredictable new chapter in Italian politics.

Berlusconi confirms split

Letta rejected the resignations of Alfano and Lupi and the three other PDL ministers on Tuesday, a signal that he valued their public backing.

Berlusconi appeared to confirm an impending party split when he decided, after a meeting with his advisers, that he will ask his lawmakers to withdraw their support for Letta on Wednesday, Alessandro Sallusti, editor-in-chief of the party newspaper, said on RAI state TV.

Sources in Letta's centre-left Democratic Party said he had not yet decided whether to call a formal vote of confidence in parliament on Wednesday and was waiting to see what emerged from a frantic round of meetings on Tuesday.

If it does not appear that he has enough support from PDL rebels, he would hand in his resignation to President Giorgio Napolitano before a confidence vote. He could then be re-appointed to try to form a new coalition in parliament, setting off a new round of negotiations.

Letta's Democratic Party (PD) has a strong majority in the lower House, but in the Senate he would need to win support from the PDL or others such as the anti-establishment Five-Star Movement, which has said it will vote against the government.