Milllions of Italian centre-left voters cast their ballots yesterday to select a nominee for Prime Minister ahead of a general election next year as the country suffers through a painful recession.

An exit poll by the Piepoli Institute showed Democratic Party leader Pier Luigi Bersani ahead of his rival Matteo Renzi but falling short of a majority, with 44 per cent.

That would mean there would have to be a run-off on December 2. The exit poll showed Renzi, the mayor of Florence, at 36 per cent.

The winner of the nomination will be one of the favourites to replace Mario Monti as Italy’s next Prime Minister, since all the most recent polls show the main centre-left Democratic Party coming first in the general election.

Late yesterday the main drama was between Bersani, 61, a cigar-chomping former communist with a liberal economic orientation, and rising star Renzi, who at just 37 is a new face in Italian politics who is inspired by US President Barack Obama.

The primary is being held at a time of deep economic crisis and political uncertainty in Italy, with a series of corruption scandals within the main parties sparking disgust with traditional leaders and voter apathy.

Both men have said they will follow the broad course of reforms set by unelected technocrat Prime Minister Monti but will seek to curb some of the more unpopular austerity measures he has advocated and do more to boost growth.

“We have to show the rest of the world that we don’t just have Monti,” Bersani, a former economic development minister, said last week.