(By Paul Virgo) Rome, May 30 - Florence Mayor Matteo Renzi on Thursday denied trying to put the heat on Premier Enrico Letta's government after a MP considered loyal to him presented a motion in parliament that would have caused turmoil if it had passed. Renzi, a telegenic 38-year-old who has been compared to the young Tony Blair, is the rising star of the Democratic Party (PD) and came second to then party chief Pier Luigi Bersani last year in the primary to select the centre-left's premier candidate for February's general election. But his share of the limelight has diminished since another young PD man, Enrico Letta, was sworn in as premier in April after being chosen by President Giorgio Napolitano to head an unprecedented left-right administration and end two months of political deadlock after the inconclusive vote. The decision by PD MP Roberto Giachetti, who is seen as close to Renzi, to present a motion on Wednesday calling for the much criticised current election law to be scrapped and replaced by its predecessor was seen by some as an act of mischief by the Florence mayor's camp. Election reform is a delicate issue for Letta's government as the PD and the other main coalition party, ex-premier Silvio Berlusconi's centre-right People of Freedom (PdL) party, are deeply divided over it, even though they both agree on the need to change the system that failed to create a clear winner in February's election. The PdL is staunchly opposed to returning to the former election law and if Giachetti's motion had passed, Berlusconi's party may have reacted by withdrawing its support from Letta's government and sinking it. The motion was soundly defeated. Renzi said he was not trying to cause trouble for the government or the PD, which has been badly hit by internal rifts after failing to win February's election despite having a massive lead in the polls two months before. But he said he was concerned that the government would dither on key reforms, including changes to the election system, widely considered necessary to make Italy easier to govern. "I'm not rushing the government. It's not true that I want to make the (life of the) government speed up," Renzi said at the Rome presentation of a book he has written. "But the government and parliament function if they pass reforms, not if they just live to get by. "None of us are interested in games or setting institutional traps in parliament or for the government. "If the ruling majority passes reforms and the political world and society start speaking the same language again, we'll be happy. Otherwise, an opportunity will have been lost". Parliament started work on Wednesday on institutional reforms, which should also include moves to reduce the number of MPs and big changes to the current lawmaking system in which bills must be approved by both the House and Senate. This is seen by many as being one of the major sources of dysfunction for Italy's institutions, which have seemed incapable of solving the country's economic ailments and purge themselves of corrupt elements in recent years. A motion presented by the parties supporting Letta and approved on Wednesday set an 18-month time limit for the reforms to be presented and approved. Although Renzi is Italy's most popular politician after President Giorgio Napolitano, according to opinion polls, he is viewed with suspicion by many within his own party. Some see his drive for the old guard of Italian politics to be "scrapped" as motivated more by personal ambition than by a desire for real change. He contributed to the internal rifts that saw Bersani resign as party leader after his handling of the post-election impasse was blasted and two candidates he selected to be Italian president were scuppered by PD revolts. "Not knowing how to distinguish between democratic leadership and one man in command seems a big problem to me," Bersani said Thursday when asked about Renzi. "It's like confusing the medicine with the illness".