Rome, April 26 - Enrico Letta took pause for thought Friday over conditions set by ex-premier Silvio Berlusconi's People of Freedom (PdL) party to agree on a broadly backed a reform government newly re-elected President Giorgio Napolitano expects the acting head of the Democratic Party (PD) to form this weekend. Letta said he was "optimistic" about giving Napolitano a "streamlined" team of 18 ministers Saturday or Sunday, when they are expected to be sworn in. PdL Secretary Angelino Alfano has made the abolition and rebate of property tax IMU a deal-breaker in the negotiations. The PD are unhappy about this and about some of the PdL names being touted as ministers but the centre-left party, which won a majority in the House but not the equally powerful Senate in February, has warned rebels will be ejected after it risked splitting and leader Pier Luigi Bersani quit over the failure of two presidential candidates. The new administration, which Letta calls "a government of service" to pass economic and institutional reforms including changing a derided electoral law, at present has the full backing of the PD and outgoing Premier Mario Monti's Civic Choice party. Berlusconi, who had what Letta called an "encouraging" phone call with the PD acting head Thursday, is expected to back it if he gets most of the ministers and policy he wants. The government should easily win a confidence vote in the House Monday and the Senate Tuesday. The PD and the PdL are the two biggest parties in parliament, having got about 30% each in February's inconclusive general election. Comedian Beppe Grillo's anti-establishment 5-Star Movement (M5S), which got 25% of the vote to produce a hung parliament, is refusing to work with them. Letta appealed to M5S to "thaw" Thursday. They rebuffed the plea but said they would vote measures on their merits. As well as a new electoral law that would produce a clear winner, the government is expected to cut the number of MPs, turn the Senate into a regional chamber, pass urgent measures including tax breaks to boost the economy and create jobs, and possibly try to reform the justice system. Italy is in its deepest recession for 20 years and unemployment has hit new heights.