Agusti Benedito has accused Barcelona president Josep Maria Bartomeu of lying about Lionel Messi's new contract, which the club are still to confirm.

Benedito, who has challenged for the club's presidency on multiple occasions in the past, is currently campaigning for signatures to force a vote of no confidence against Bartomeu and the Barcelona board in the wake of a dreadful summer for the Catalan giants. Benedito accuses the current regime of causing a "serious institutional crisis" and has already gathered over 10,000 signatures from frustrated supporters.

Messi entering the final year of his contract has heightened concerns over how the club is being run at the top level. The club confirmed in July they had reached an agreement with the Argentina international to extend his deal until 2021 but are still to officially confirm the deal.

Bartomeu has publicly insisted on more than one occasion however that Barcelona fans should have nothing to fear and in September, claimed Messi's father had already signed a 'triple' contract on his son's behalf with a stunning release clause worth €300m (£264m, $358m).

He insisted in subsequent interviews the announcement is coming soon but was quoted as saying by Marca last week that it could be the end of the year before an official announcement is made.

Benedito has now accused Bartomeu of keeping fans in the dark over the deal, insisting a deal signed by Messi's father means nothing and that the president's presence in the negotiations may be the root of the problem.

"That contract, without Leo's signature, is not valid," Benedito was quoted as saying by SPORT. "Even though his father has signed, it needs the player's signature. This doesn't help with getting it signed. It's possible that Bartomeu's presence is the main obstacle. I hope that the president explains everything truthfully. It's not the first time he's lied."

Benedito, who leads the group behind the motion to force a vote of no confidence at the club, needs to collect 16,570 signatures by 2 October, although Barcelona insist the deadline is 27 September.

Having already collected 10,715, he remains confident of reaching that number which would force s club member vote on whether the board remains in power.

"We are a little ahead of where we expected to be so we are really happy. We have 12 days left to get the rest of the signatures. It is a big challenge, but one which is more within reach.

"We are convinced we will be able to put this board to a vote to decide whether they continue or if they have to leave."