Italy's embattled prime minister, Silvio Berlusconi, plans to address parliament on Thursday, after his center-right coalition failed to pass a key budget provision on Tuesday.

In his speech, Mr. Berlusconi is expected to ask for a confidence vote to be held on Friday. He would have to resign if he loses. Italy's next elections are scheduled for 2013.

Mr. Berlusconi downplayed the importance of Tuesday's failed vote, calling it an accident caused by the absence of several coalition members from the chamber. But others have asserted that some lawmakers intentionally stayed away from the vote to send a message about a split in the coalition.

Among those missing were Economy Minister Giulio Tremonti and Mr. Berlusconi's key coalition ally, Northern League Party leader Umberto Bossi.

President Giorgio Napolitano on Tuesday expressed concern about the current government's viability, describing acute tensions and uncertainties within the government and coalition.

The 75-year-old Mr. Berlusconi has dismissed opposition calls for his resignation despite an administration weakened by a debt crisis and bickering over austerity measures to help solve the problem. He also is the defendant in several ongoing sex and corruption trials.