Italy's ruling parties asked Sergio Mattarella on Saturday to carry on as president for a second term after failing to find a compromise candidate in a week of often fraught voting in parliament.

Mattarella, 80, has always ruled out remaining in office and made no immediate comment, but with the country's political stability at risk, it looked highly unlikely he would be able to resist the pressure.

Prime Minister Mario Draghi spoke to Mattarella on Saturday, telling him he needed to stay in place "for the good and stability of the country," a government source said.

The move followed five days of stalemate in parliament, with the main political blocs incapable of agreeing on a candidate who could win broad backing among lawmakers.

"The Italians do not deserve any more days of confusion," said Matteo Salvini, head of the rightist League party.

"Let's reconfirm President Mattarella ... and Draghi, and immediately get back to work this afternoon. The problems of the Italians won't wait," Salvini added.

The president is a powerful figure in Italy who gets to appoint prime ministers and is often called on to resolve political crises in the euro zone's third-largest economy, where governments survive barely a year on average.

Unlike in the United States or France, where heads of state get elected in a popular vote, in Italy, 1,009 parliamentarians and regional representatives chose the winner in a secret ballot, which party leaders sometimes struggle to control.

Threatening to ignore their chiefs and take charge of the situation themselves, lawmakers have been increasingly backing Mattarella in the daily ballots, with his tally rising to 336 ballots on Friday, up from 160 on Thursday and 125 on Wednesday.

A successful candidate needs 505 votes to win. After an inconclusive ballot on Saturday morning, a second vote was scheduled for later in the day.

"Parliament wants Mattarella," La Repubblica daily said in a front-page headline.

The repeated failure to find a consensus has poisoned the political atmosphere, with potentially dangerous consequences for the stability of the coalition government.

Draghi himself has made clear he would like the job of president, but the main parties refused to put his name to a vote, partly out of fears that the abrupt switch of roles could cause the fragile government to implode.