Italian Prime Minister Silvio Berlusconi is facing a key confidence vote in parliament amid questions over his handling of the economy and personal scandals. Mr Berlusconi is expected to survive but the margin could be narrow. Italy's government credit rating was recently downgraded and parliament failed to back a key part of the budget this week, triggering the vote. Mr Berlusconi also faces trial on sex, bribery and abuse of power charges. 'Cohesive majority' The BBC's David Willey in Rome says Mr Berlusconi remains characteristically upbeat about his chances of winning the vote, although some members of his governing Freedom Party have left their support in doubt. The environment minister has said she will not support the government after she learned that her ministry is to be abolished as part of Italy's new austerity package. Our correspondent says that even if Mr Berlusconi survives, most Italians are betting on a general election as early as next spring. Mr Berlusconi needs a simple majority of 316 of the 630 MPs. His Freedom Party and main coalition ally, the Northern League, have a combined 293 seats. The vote is expected to begin at about 10:30 GMT. The confidence vote was forced after parliament on Tuesday failed to approve one article of the budget by a single vote. It later emerged that the finance minister had failed to meet the ballot deadline by 30 seconds. Demanding the confidence vote, opposition leader Pierluigi Bersani said: "The government is not coping with the situation. The problems have all been laid out, but he only knows how to stay nailed to his seat by using tricks." Mr Berlusconi, 75, insisted he had a "cohesive majority" in parliament. "There is no alternative to this government. Early elections would not solve the problems we have. A political crisis now would mean victory for the party of decline, catastrophe and speculation." Despite facing three trials - including for allegedly paying for sex with a 17-year-old girl - and an all-time-low approval rating of 24%, Mr Berlusconi has shown remarkable staying power. He has always maintained his innocence. On Saturday, he also faces a mass demonstration in Rome - similar to recent ones in New York and Madrid - against austerity measures and financial mismanagement. Italy is considered vulnerable in the current eurozone crisis, with the highest public debt in the grouping. The country approved an austerity package last month to balance the budget by 2013 but its central bank chief this week urged the government to introduce more measures to stimulate growth.