ROME (Reuters) - Italy's center-right parties hammered their center-left rivals in mayoral elections, official results showed on Monday, putting pressure on the ruling Democratic Party (PD) ahead of a national vote due in less than a year.
An alliance of Silvio Berlusconi's Forza Italia and the anti-immigrant Northern League won 55 percent of the votes in Genoa, the northern port city that was a left-wing stronghold but which the right will now govern for the first time in more than five decades.
PD leader Matteo Renzi, who has been seeking to make a comeback since stepping down as prime minister in December, was the clear loser in Sunday's vote, though polls show his party is still one of Italy's most popular nationally.
"It could have gone better," Renzi said in an early-morning Facebook post. "The overall result isn't great. Some losses hurt, starting with Genoa and L'Aquila," he said, referring to another former left-wing bastion city that fell to the right on Sunday.
Four-time Prime Minister Berlusconi hailed victory.
"The center-right is the largest coalition in the country," he said in a statement. The results set the stage for the coalition "to get to work on the decisive challenge of returning to govern the country," he said.
The center-left has governed Italy for four years, during which time the economy grew by only half the euro zone average. Three different PD premiers have struggled to shore up a banking system strangled by bad loans, and to manage half a million migrants who came by boat from North Africa.
At 46 percent, turnout was very low by Italian standards, with many of the 4.3 million eligible voters probably choosing to go to the beach on the sweltering summer Sunday rather than the ballot box.
Sunday's vote -- the second round for cities where no one candidate won more than 50 percent two weeks ago -- is one of the last before a general election due by the end of May 2018, but it may not be a reliable indicator of what will happen then.
The first-past-the-post voting system used at the municipal level, which favors coalitions, may not be replicated at a national level, where a proportional system is now in place.
But Sunday's result could help unite center-right parties which are in competition nationally. Their strong showing suggests if they come together under a single leader they would be a force to be reckoned with at the general election.
The center-right triumphed in 15 of the largest cities in Sunday's run-off, including Verona, Monza, Como, Piacenza and Pistoia, compared with four for the center-left.
Overall, the center-right won 79 cities over both rounds of voting, gaining control of 25 new cities, while the center-left won 76, losing 30 administrations, Forza Italia spokeswoman Deborah Bergamini said.
"We knew the winds had shifted," Bergamini told Reuters. "This is a major setback for the PD."
Genoa is the latest of a string of defeats in the PD's traditional strongholds. Last year it lost Turin, Italy's fourth-largest city, and the capital Rome, both to the 5-Star Movement, which was only founded eight years ago.
5-Star, which opinion polls say is slightly more popular than the PD nationwide, performed very badly in the first round of voting on June 11 and made the run-off in only one of the 25 largest cities. It added eight mayors to its modest tally.
"We now have 45 mayors, up from 37 before, which is an increase of 20 percent," 5-Star founder Beppe Grillo said on his blog. "Every damned election we are growing and that is what counts."
The northern city of Parma went to the incumbent mayor who was elected as 5-Star's first ever mayor in 2012, but ran as an independent after falling out with the movement's leadership.
Editing by Robin Pomeroy