Berlusconi's defiance over the possible sanction is unique in Europe's recent political history and threatens the coalition between his People of Freedom (PDL) and the centre-left Democratic Party (PD).
As the eurozone's third biggest economy struggles to exit a recession that has led to record unemployment, the 76-year-old former prime minister and billionaire tycoon has once again taken the political centre stage.
A Senate committee began its meeting to discuss his ejection, even though stalling tactics from Berlusconi's supporters could drag the process on for months before a compulsory final Senate vote.
Berlusconi has complained that a new law against criminals in parliament adopted last year with the aim of cleaning up Italian politics and approved with votes from his own party in fact violates his rights.
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The three-time premier has appealed to the European Court of Human Rights in Strasbourg, arguing that the law should not apply for convictions relating to crimes committed before its adoption, as in his case.
The law would also prevent Berlusconi from taking part in the next general election set for 2018.
Some of Berlusconi's critics have pleaded with him to resign voluntarily and spare Italy more embarrassment.
PD leader Guglielmo Epifani has warned that Italy risks looking like a "banana republic" internationally.
Nichi Vendola, leader of the leftist SEL party, said the case is "unique for a Western democracy".
Berlusconi could lead his party from outside parliament but expulsion would be a blow as he has been a lawmaker ever since entering politics in 1994.
An appeals court will also begin hearings on October 19 to decide whether Berlusconi should be temporarily banned from holding public office for one to three years.