(By Paul Virgo) Rome, July 26 - Premier Enrico Letta's government faces a battle with opposition parties determined to obstruct the its drive to push a reform bill through parliament before the summer recess. The anti-establishment 5-Star Movement (M5S) and the leftwing SEL want the bill establishing procedures to introduce changes to the Constitution to revamp Italy's public institutions and make the country easier to govern delayed until after the recess in September. The M5S has vowed to continue to use obstructionist tactics after it drew out final approval in the Lower House of a separate decree on growth measures until Friday by deliberately extending the debate of the measure. The growth package, which now passes to the Senate, won confidence vote on Wednesday and the filibustering caused knock-on delays to the examination of other measures. M5S House whip Riccardo Nuti also called on President Giorgio Napolitano to intervene in the reform bill row on Friday. "An intervention from the president would suffice," said Nuti. "When we had a meeting with him he was quite critical of setting the schedule for the reform bill by the end of July. "Why doesn't he make his voice heard and say what he said to us?". The bill regards the procedures for the institutional reforms that are set to be framed by a panel of 40 members of parliament after consulting a committee of 35 experts on the Constitution. Changes to the Constitution should include stripping the Senate of law-making powers and turning it into a regional assembly and a rewrite of the electoral law. At present the Senate has the same powers as the House, and legislation has to be approved in the same form in both houses, making lawmaking a drawn-out affair. The current electoral law has been widely criticised because it does not let voters pick their MPs and tends to produce different majorities in the two houses, as happened in February's general election which led to two months of deadlock. Letta has said he will resign if the reforms are not framed in 18 months. The obstruction problem is another headache for Letta, who faces a tough task in keeping his coalition together given policy differences between his centre-left Democratic Party (PD) and ex-premier Silvio Berlusconi's centre-right People of Freedom (PdL) party. The PdL also may pull the plug on the government if the Constitutional Court on Tuesday upholds a four-year conviction against Berlusconi for fraud at his media empire that comes with a five-year band from holding public office. Letta's executive also faces threats from his own party, with many parts of the PD unhappy about it being in government with their long-standing bitter rivals in the PdL. At a party meeting Friday caretaker PD Secretary Guglielmo Epifani said the party will hold a congress to elect a new permanent leader by the end of November. Epifani said the new PD leader should focus on the party and automatically not be its premier candidate the next time there are elections. PD rising star Matteo Renzi, who had led some internal grumblings about Letta's government, is considering running to be party leader, but wants the position to come with premier-candidate status. Letta's cabinet, meanwhile, on Friday approved a bill that will strip many of the powers of Italy's provincial governments ahead of plans for them to be abolished completely as part of the Constitutional reforms. The move to abolish the provincial governments is part of a drive to reduce the cost of Italy's political apparatus as the country' struggles to emerge from its longest recession in over two decades. Letta's government has also presented a bill to phase out public funding of political parties and there are plans to cut the number of lawmakers in parliament too.