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By Gavin Jones and Angelo Amante
ROME, Oct 18 (Reuters) - Centre-left candidates looked set to win resounding victories in mayoral elections in Rome and Turin, according to exit polls on Monday that predicted they had swept aside centre-right opponents in run-off ballots.
If the exit polls are confirmed they will complete a round of centre-left triumphs in Italy's largest cities and mark a setback for the rightist alliance which is nonetheless favourite to win the next national election due in 2023.
Centre-left candidates had already easily won Milan, Naples and Bologna two weeks ago without the need for a run-off.
The results are not expected to have immediate repercussions for the stability of Prime Minister Mario Draghi's national unity government, analysts say.
In Rome, former Economy Minister Roberto Gualtieri from the Democratic Party (PD), was seen winning 59-63% of the vote against the right's Enrico Michetti on 37-41%, according to an exit poll by the Opinio consortium of pollsters for RAI state television.
In Turin, the PD's Stefano Lo Russo was seen winning with 56-60% against the right's Paolo Damilano on 40-44%.
Both cities were previously run by the 5-Star Movement, whose candidates were defeated in the first round.
In Rome, Gualtieri lagged by three points in the first ballot, but seems to have picked up most of the votes of those who supported the first-round losers -- 5-Star's outgoing mayor Virginia Raggi and Carlo Calenda, an independent centrist.
Gualtieri faces an arduous task to fix the capital's most chronic problems, including haphazard trash collection and a dilapidated and inadequate public transport system.
The results are a blow 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 recent opinion polls.
However the rightist bloc, which includes Silvio Berlusconi's Forza Italia, draws most of its support from small towns and villages, and analysts say it may be misleading to draw national conclusions from the mayoral votes.
"Rightwing voters tend to mobilise more at national elections than at local ones," said pollster Antonio Noto of the Opinio Consortium.
The turn-out in the city elections was particularly low, with under 50% of eligible voters casting a ballot.
The next parliamentary election is shaping up as a battle between the right and a centre-left bloc led by the PD and the 5-Star Movement.
Among other cities at stake in the mayoral run-offs, the right looked at risk of losing a huge first-round lead in north-eastern Trieste, where the exit poll pointed to a neck-and-neck race with the centre-left.
Another closely watched city is Varese, where Salvini will be banking on holding on to the traditional League stronghold close to the Swiss border. (Reporting by Gavin Jones and Angelo Amante, editing by Crispian Balmer)