ROME, Oct 4 (Reuters) - Centre-left candidates are set to win Italy"s big cities in local elections, partial results showed on Monday, with Rome"s incumbent mayor Virginia Raggi of the 5-Star Movement headed for defeat. The results are not expected to have immediate repercussions for the stability of Prime Minister Mario Draghi"s national unity government, analysts said. Italy"s four largest cities - Rome, Milan, Naples and Turin - and more than 1,000 smaller centres held mayoral elections on Sunday and Monday, with a run-off due in two-weeks" time in cities where no candidate reaches 50%. Centre-left candidates are seen winning without the need for a run-off in the financial capital Milan, Naples and Bologna. The centre-left had been expected to sweep up in most of the cities, but the margins of victory are larger than forecast. The outcome is a setback for Matteo Salvini and Giorgia Meloni, respective leaders of the rightist League and Brothers of Italy which dominate a conservative alliance that leads at national level, according to opinion polls. It also confirms the decline of 5-Star, whose shock victories in Rome and Turin five years ago paved the way for its triumph at 2018 national elections when it was the largest party with 33% of the vote. "The result suggests that the prevalent view during the last two years that the centre-right would certainly win national elections needs to be reconsidered," Giovanni Orsina, politics professor at Rome"s LUISS university, said. However the rightist alliance, which includes Silvio Berlusconi"s Forza Italia, draws most of its support from small towns and villages and Orsina cautioned against drawing clear national conclusions for the mayoral vote. FEUDING Some 12 million Italians were eligible to vote out of an adult population of around 45 million. The turnout was around 55%. The count will probably not be completed until Tuesday, but analysts said the trend was irreversible in the main cities. "We have shown that the right is beatable ... we have got back in touch with the sentiments of the country," said Enrico Letta, leader of the centre-left Democratic Party (PD) which emerged as the main winner. Salvini blamed the right"s poor showing on internal feuding which delayed its selection of joint candidates in several cities. Centre-left incumbent Giuseppe Sala was estimated to win 57% in Milan, ahead of the centre-right candidate on 32%, giving him control of city hall without the need for a run-off on Oct 17-18, according to projections by Opinio, a consortium of pollsters for state broadcaster RAI. In Rome, the right"s Enrico Michetti, a local lawyer and radio host, led with 30.5% of the vote, with the centre-left"s Roberto Gualtieri, a former Economy Minister from the Democratic Party, on 27%. However, Gualtieri is favourite to win the run-off, when he is expected to take most of the votes of the candidates defeated in the first round, Raggi and Carlo Calenda, an independent centrist, who were paired on 19%. In Naples the centre-left"s Gaetano Manfredi, a former minister backed by the PD and 5-Star, was headed for a crushing victory, while in Turin the centre-left candidate has a clear lead but will probably need to go to the run-off. In a consolation for the right, it was seen easily winning a regional election in Calabria, the southern toe of the Italian boot, where it was already in power.