Hot favourite Luigi di Maio, 31, the movement's most popular politician, is running in an internal ballot against seven unknowns and is widely believed to have the vote in the bag - prompting criticism from Italy's mainstream political parties and media.
Telegenic Di Maio will go up against six totally unknown candidates and a low-profile senator in an electronic vote this week that has both amused and irked traditional parties and the country's mainstream media.
His rivals include an aerospace engineer, a computer consultant, a hotel cook, and a business owner. Apart from senator Elena Fattori, the others are involved in the party on a local level; as part of the movement's 'direct democracy' policy, any member who has held an elected position can stand.
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"Di Maio's lone run for the Five Stars," said the La Stampa moderate daily, while the left-wing Il Fatto Quotidiano asked: "Do you want Luigi or Di Maio? One real candidate and seven fakes".
Critics say the platform allows no independent review of the voting process and rivals on the left and right have accused the movement - which summarily expels dissidents - of holding a "joke" ballot.
Photo: Marco Bertorello/AFP
"A M5S primary like in North Korea," said PD senator Andrea Marcucci.
But Di Maio said on Wednesday that there were "no divisions" within the party and that, if chosen by the party's members, he would be working only as "the head of a team".
The snappily-dressed lower house deputy has been openly groomed to run for prime minister in the spring 2018 general election by comic Beppe Grillo, who co-founded the Five Stars (M5S) in 2009.
The party uses an online voting system to choose candidates for official positions - as well as to vote on draft legislation and policies - as part of its aim of 'direct democracy'.
However, the voting system, which is officially called a "consultation tool", has come under fire for a lack of transparency. A Sicilian court this week confirmed the suspension of the results of the Five Star Movement's regional primaries following a legal appeal by a candidate who was barred from the ballot by party leadership.
But Grillo said the candidate chosen by the primaries, Giancarlo Cancelleri, will represent the party despite the court's decision, arguing that there was "no time" to re-run the primaries before the November 5th vote in Palermo.
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Photo: Marco Bertorello/AFP
Former members have criticized the leadership's tight control over the system, and earlier this year, the party ended up without a candidate for Genoa's council elections after the leadership banned the winner of the vote, Marika Cassimatis from standing.
Grillo said that some of her positions were "contrary to the principles of his movement", though he did not expand on exactly what these positions, or the party principles supposedly violated, were, instead calling on members to "trust me".
The movement bases much of its appeal on fighting corruption and has promised a referendum on membership of the euro - though it recently softened its tone on this issue, saying such a referendum was not a top priority but a "negotiating tool". It first emerged as a major political force in 2013 and went on to score stunning local victories, including taking control of Rome and Turin last year.
And despite a poor performance at local elections in June, for months now the Five Stars have been neck and neck in the polls with the centre-left ruling Democratic Party (PD), with recent projections showing they would win almost 30 percent in a national race.
The winner of the primaries will be announced late on Saturday at a Five Star meeting in the northern coastal city of Rimini.
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