(By Paul Virgo) Rome, June 24 - Premier Enrico Letta will meet Silvio Berlusconi and the leaders of the other parties supporting his left-right government over the next two days, government sources said Monday. Letta's government is based on an unnatural alliance between his own centre-left Democratic Party (PD) and Berlusconi's People of Freedom (PdL) party. The parties, bitter rivals for 20 years, were forced to form a coalition in April to end two months of political deadlock after February's general election failed to produce a clear winner. But since then the PdL and the PD have been almost constantly bickering. The PdL has threatened to sink the government if it does not scrap an unpopular property tax called IMU and refund revenues raised from it in 2012. The centre-right party is also insisting that the government avert a 1% rise in the top band of value added tax (VAT) scheduled for July. Letta told State broadcaster Rai on Sunday that the government would find a solution on VAT, with the rise expected to be postponed at least until December, but he also warned the PdL that "ultimatums don't serve anyone". Later on Monday the premier is set to meet his predecessor Mario Monti, whose small centrist Civil Choice party also supports the government. He will see PD Secretary Guglielmo Epifani early on Tuesday and is expected to have talks with Berlusconi Tuesday evening, the sources said. Early on Monday, meanwhile, Letta had two hours of talks with the leaders of Italy's three big trade-union confederations to discuss the country's jobs emergency. Letta has said combatting unemployment is the top priority for the government as Italy's jobless rate has hit a record high of 12% and around four in 10 young people aged 15-24 are out of work. The Italian premier successfully lobbied for this week's summit of European Union leaders to focus on youth unemployment. The government is hoping to pass a package of measures to combat youth unemployment at a cabinet meeting on Wednesday so Letta can show it is leading by example at the summit in Brussels later in the week. But the big unions, CGIL, CISL and UIL, have expressed doubts about how effective those measures will be and accused the government of delivering words instead of action at a joint rally in Rome on Saturday. The situation for Letta's government has been made even more delicate by Berlusconi's legal troubles. On Monday a Milan court was set to give its verdict in a trial into allegations Berlusconi, 76, paid for sex with an underage prostitute and abused his power to try to cover up the affair. Last week Berlusconi failed in a bid to have the Constitutional Court strike down a four-year conviction for tax fraud at his media empire along with a five-year ban from public office. Senior PdL officials have said the party's lawmakers will quit if the sentence is upheld by the supreme Court of Cassation and becomes definitive. The ex-premier is also appealing a one-year term for involvement in the publication of an illegally obtained wiretap and facing indictment for allegedly buying Senators to topple a centre-left government.