Berlusconi party loses key Sicily vote

Silvio Berlusconi's People of Freedom party lost to an anti-Mafia candidate in the Sicily election. (AAP)

Silvio Berlusconi's People of Freedom party lost to an anti-Mafia candidate in the Sicily election. (AAP)

Former Italian prime minister Silvio Berlusconi's party has lost a regional election in Sicily seen as a barometer for national polls.

Italian ex-prime minister Silvio Berlusconi's People of Freedom party (PDL) has lost a key regional election in Sicily seen as a barometer for national polls due in April, handing victory to a centre-left anti-Mafia candidate.

With more than 50 per cent of votes counted, Rosario Crocetta of the Democratic Party (PD) was leading with 30.88 per cent, ahead of the PDL's Sebastiano Musumeci with 24.90 per cent, robbing him of what was once the centre-right's stronghold on the Mediterranean island.

The outsider, the anti-politics Five Star Movement, surprised observers by garnering 18.46 per cent amid rising sentiment against the established parties and anger over rampant corruption, particularly in the Mafia stronghold.

"It's the first time that a candidate for the left is elected as regional governor, it's the first time that an anti-Mafia candidate wins," declared a victorious Crocetta, 61, an openly gay campaigner against organised crime.

"Today is more than an election result, it is a date with history," Crocetta, who lives under police protection after threats to his life, told journalists.

Pier Luigi Bersani, head of the PD party, called the result "historic".

The regional vote comes at time of deep political uncertainty in Italy, with divisions and bickering within the main parties. Frustration is also running high over waste and corruption in the recession-hit country.

Italy's economic crisis is particularly acute in Sicily, which came close to bankruptcy this year, and where nearly 40 per cent of young people are unemployed.

The defeat comes as a blow to the beleaguered PDL party, which has been struggling with internal divisions and embroiled in corruption scandals.

The political situation was aggravated at the weekend when Berlusconi threatened to withdraw support for the government - a move that could spark panic among markets, which have placed their faith in Prime Minister Mario Monti.

Berlusconi's PDL is the biggest in parliament and could force an early election if it withdraws its backing for Monti's technocrat government, but the loss in Sicily is a decisive setback.

The billionaire, who was found guilty on Friday of tax fraud, had announced last week that he would not run for prime minister in the 2013 election, but later vowed to remain in politics to reform the justice system that found him guilty.

The Sicily election was held early because the island's last governor, Raffaele Lombardo, was forced to resign in July after allegations of Mafia collaboration and a crisis in the public finances of the autonomous region.

His predecessor, Salvatore Cuffaro, is serving a seven-year prison sentence in Rome for aiding and abetting the Mafia in its home turf in Sicily.