Silvio Berlusconi hit out Saturday at former loyalists in his centre-right party who have set up a "renewal" faction led by the media tycoon's ex-protege Angelino Alfano.
The billionaire media tycoon blamed the split, without ever naming Alfano, on "differences not of policy or values but between personalities who have created a poisonous atmosphere".
Alfano, who announced the "divorce" after late-night talks on Friday, stayed away along with some 50 other defectors from a meeting Saturday of Berlusconi's People of Freedom (PDL) party.
During a rambling speech lasting an hour and a half, the scandal-tainted Berlusconi, 77, drew frequent applause.
Admitting to having had a sleepless night, once appearing on the verge of fainting before recovering himself, the media and construction baron expressed his "sadness" at the break-up.
In a conciliatory gesture, Berlusconi added however that Alfano's grouping would be a "necessary member" of the 200-strong centre-right voting bloc.
The PDL meeting was meant to be a happy event at which the party would be rebaptised Forza Italia ("Go Italy"), the sporty name Berlusconi used when he first launched the party in 1994.
Alfano, whose faction is to be called the New Centre Right, said Friday he would not be part of the reborn Forza Italia in "a choice that I never thought I would make".
The 43-year-old Sicilian lawyer said he made the decision because "these past few weeks have shown to what extent extreme forces have prevailed within our movement", referring to a belief by his supporters that Berlusconi was pandering to hardliners.
Berlusconi's party has been in turmoil since September when he tried to bring down Italy's uneasy left-right coalition government by withdrawing his ministers, but was forced into a humiliating climbdown when they refused to heed his orders.
The five ministers -- all Alfano supporters -- will stay on as members of the rump PDL, meaning that Forza Italia will not be represented in the government.
The daily La Stampa described the break-up as the "first post-Berlusconi act" with an immediate consequence: "The government is saved, with a new, smaller but also more united (parliamentary) majority."
Berlusconi will face another humiliation on November 27, when the Senate votes whether to eject him from parliament's upper chamber under a law banning convicted criminals from the body.
The move comes after the Italy's supreme court on August 1 turned down his final appeal in a tax fraud case, handing Berlusconi his first-ever definitive conviction in a long history of legal woes. Berlusconi has asked to serve his 12-month sentence by carrying out community service.
Ejection from the Senate would see Berlusconi without a seat in parliament for the first time since he first burst onto Italy's political scene nearly 20 years ago.