* Voting started at 1000 GMT in 5th attempt to elect president
* Centre-right says to vote for Senate head Casellati
* Needs defectors from the other side, in secret ballot
* Draghi is a contender, but his prospects have clouded
* Parliament to hold two votes per day from Friday


Italy's parliament began a fifth attempt to elect a new president on Friday, with the centre-right parties saying they will try to push through Senate speaker Elisabetta Casellati for the powerful role.
That would be a direct snub to the centre-left after days of fruitless talk about the need to elect a consensus candidate that can draw broad cross-party support.
Casellati is from Silvio Berlusconi's Forza Italia party, one of the three groups that make up the conservative alliance along with the rightist League and Brothers of Italy.
Much is at stake. The Italian presidency comes with a seven-year mandate and has considerable power to resolve political crises that regularly batter the country, including appointing prime ministers and dissolving parliament.
It remains to be seen whether the right's confrontational approach will be successful, as it lacks the votes to elect the president on its own and must rely on unaffiliated lawmakers or centre-left defectors in the secret ballot.
Some of these votes many come from the 5-Star Movement, which is the largest group in parliament but is internally divided and difficult for its leader, former premier Giuseppe Conte to control.
Voting started at 1000 GMT.
Prime Minister Mario Draghi remains a contender, but his prospects have faded this week, with many lawmakers clearly reluctant to back him, partly because they fear any change to the government could trigger an early election.
Giorgia Meloni, leader of the Brothers of Italy, has been pushing for a show of force from the right and said she was pleased it would finally try to get its own candidate elected instead of continuing to cast blank ballots or abstain.
"The centre-right has to show it is compact," she said, amid speculation that some lawmakers from the bloc will defy their leaders' instructions.
Enrico Letta, leader of the centre-left Democratic Party, said on Friday that the right could not longer be trusted.
"They have taken us for a ride for the last three days," he told reporters ahead of a centre-left meeting in parliament.
Neither the centre-right nor centre-left groups put forward any names for Thursday's vote - the fourth this week - after various parties had shot down a raft of possible contenders, opening the way for intense, behind-the-scenes haggling.
If the centre-right's move should fail on Friday, it may eventually open the way to a second mandate for Sergio Mattarella, even though the outgoing president, who is 80, has so far ruled this out.
Two government members told Reuters on Thursday that the re-election of Mattarella was a strong possibility.
With tempers fraying after four inconclusive days, party representatives decided on Friday that from now on there will be two rounds of voting per day, instead of one, until a president is elected.
Unlike in the United States or France, where presidents get elected in a popular vote, in Italy some 1,009 parliamentarians and regional representatives pick the head of state in a secret ballot, which party leaders sometimes struggle to control.
To be elected a candidate must win an absolute majority, or 505 votes.
Even though the main party chiefs instructed their lawmakers to abstain or cast blank ballots in Thursday's ballot, Mattarella still got 166 votes, more than anyone else for the second day running, though well below the required 505.
Aside from Draghi and Mattarella, numerous other candidates are cited for the job, often only to be shot down by one side or the other in a matter of hours.
These include Elisabetta Belloni, a career diplomat who heads the secret services, and Sabino Cassese, an 86-year-old former constitutional court judge.
Other possible contenders floated in the media include former lower house speaker Pier Ferdinando Casini, former premier Giuliano Amato, Senate speaker Elisabetta Casellati and Justice Minister Marta Cartabia, who previously chaired the constitutional court.
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