Exit polls have shown the Sicily election will be a key indicator for Italy's general election. The vote is a neck-and-neck race between the centre-right and the populists.
Silvio Berlusconi's centre-right coalition has taken a slight lead against the anti-establishment 5-Star Movement in Sicily's regional elections, according to initial projections on Monday based on the vote count.
Sunday's ballot, which is seen as a crucial test of national trends ahead of forthcoming parliamentary elections, could mark a striking comeback for the 81-year-old, four-time prime minister Berlusconi and a blow to the ruling centre-left.
A victory for the maverick 5-Star, on the other hand, would hand it control of its first ever Italian region and would be likely to consolidate its position as the country's most popular party nationally.
RAI state television said the centre-right's candidate for governor of the island, Nello Musumeci, was likely to get 36 percent of the vote, with 5-Star's candidate Giancarlo Cancelleri on 34 percent.
Private channel La7 put Musumeci on 37.3 percent and Cancelleri on 36.8 percent.
The centre-left, led by Matteo Renzi's ruling Democratic Party, looked certain to finish a distant third after internal feuding wrecked its chances of retaining power on the Mediterranean island that it had governed since 2012.
Its candidate Fabrizio Micari was seen at least 15 points behind the frontrunner in both surveys, followed by Claudio Fava, the candidate of a cluster of left-wing parties.
The national election, to be held by May at the latest, is almost certain to produce a hung parliament, polls suggest, but a resurgent centre-right coalition with Berlusconi at the forefront looks set to win most votes and seats.
The billionaire media tycoon was widely written off after being expelled from public office following a tax fraud conviction in 2013, but he returned to the political fray after open heart surgery last year and campaigned actively in Sicily.