* Campaigning banned ahead of voting on Sunday and Monday
* Berlusconi breaks silence to launch attack on magistrates
* Anti-establishment movement increases uncertainty
* Weak government could destabilise euro zone
By Catherine Hornby
ROME, Feb 23 Italy pressed citizens to get out and vote in one of the most closely watched elections in years on Sunday and Monday, with markets on edge at the prospect of a political stalemate that could reignite the debt crisis.
A campaigning ban kicked in the day before the vote but centre-right leader Silvio Berlusconi, on trial for a sex crime, broke the rules to launch an attack on magistrates, saying on Saturday that claims he held "Bunga Bunga" parties were a sham.
Comedian-turned-campaigner Beppe Grillo had stolen the spotlight during final rallies on Friday evening, attracting hundreds of thousands to a central Rome square to hear his furious tirades against corrupt politicians and bankers.
The Interior Ministry urged some 47 million eligible voters to head to the polls and said it had made preparations for bad weather, including snow in some regions, to ensure that everyone could have the chance to cast their ballot.
"Elections are a fundamental moment for a democracy and we want all our citizens to experience them in the best way possible," Interior Minister Anna Maria Cancellieri said in a video posted on the ministry's website.
Final polls two weeks ago showed centre-left leader Pier Luigi Bersani with a five-point lead, but analysts disagree about whether he will be able to form a stable majority that can push through the economic reforms Italy needs to exit recession.
Bersani is now thought to be just a few points ahead of Berlusconi, the former prime minister who has promised tax refunds and staged a media blitz to regain support.
On Saturday the 76-year-old tycoon, who faces several trials on charges ranging from fraud to sex with an underage prostitute, broke the campaign silence, accusing Italy's magistrates of inventing crimes to discredit him abroad.
"They spread the story in Europe that I was ridiculous by launching this attack on me with Bunga Bunga which was a sham, based on nothing," Berlusconi told reporters at his AC Milan soccer club's training ground.
He added that magistrates in Italy were "more dangerous than the Sicilian mafia".
Another factor of uncertainty that has thrown the vote wide open is the stunning rise of Grillo, who wants to restructure Italy's massive public debt and hold a referendum on retaining the euro currency.
Huge crowds have turned up to rallies on his "Tsunami Tour" to hear him rail against corruption and austerity, underlining the extent of popular rage against traditional parties and the capacity for his 5-Star Movement to shake up the elections.
"Grillo is saying the things that all ordinary Italians are thinking, he is giving us hope," said 41-year-old Luca Pennisi, who makes pastries for a cafe in the capital where several customers were still unsure who to vote for.
"It's time to change the system, get rid of the old politicians, and stop wasting public money," he said.
Grillo was seen winning about 16 percent in the last polls, making his movement the third-largest electoral force. Experts believe he may have built on that score, helped by a strong online campaign and a string of scandals surrounding Italy's political elite.
The most likely - and many say the most stable and pro-reform result from the election - still appears to be a governing alliance between Bersani and outgoing Prime Minister Mario Monti's centrist grouping, which would need to win enough senators to boost the centre-left.
But Monti, an economics professor and darling of the markets, is believed to be fading after a lacklustre campaign, and some experts have said he may fall below the 8-percent threshold to win Senate seats in some regions.
Whatever government emerges from the vote will have the task of pulling Italy out of its longest recession for 20 years and reviving an economy that has been stagnant for two decades.
The main danger for Italy and the euro zone is that the election produces a weak government incapable of taking firm action, which is likely to rattle investors and could ignite a new debt crisis.
Monti replaced Berlusconi in November 2011 after the media billionaire brought the euro zone's third-largest economy close to a Greek-style financial meltdown while he was embroiled in a series of scandals.
The former European Commissioner launched a tough programme of spending cuts, tax hikes and pension reform which helped to sharply reduce Italy's borrowing costs and restore the country's credibility abroad.
But economic austerity has fuelled anger among Italians grappling with rising unemployment and shrinking disposable incomes, encouraging many to turn to Grillo, who has tapped into a national mood of disenchantment.