Barcelona maintain that Lionel Messi will sign his contract extension despite former club president Joan Laporta's suggestion he could leave if current chief Josep Maria Bartomeu is not removed from his position.

Messi's current deal expires next summer but Barca announced in July that an agreement had been reached for a new four-year deal, running until 2021.

However, the new terms have not yet been signed and reports over the weekend claimed Manchester City are prepared to pay the Argentine's €300 million buyout clause.

"If we want Messi to continue to be happy at Barca we have to get rid of Bartomeu immediately," Laporta wrote on Twitter after the links with City had surfaced.

Lionel Messi is still yet to sign the contract he agreed in July and has been linked with Manchester City. Manuel Queimadelos Alonso/Getty Images

However, Barca sporting director Robert Fernandez downplayed the idea Messi could leave the club and said that the contract extension will be signed soon.

"The agreement for Messi's renewal is total on both sides," he told beIN after Barcelona began the new La Liga season with a 2-0 win against Real Betis on Sunday.

"We are looking for the right moment to sign it, there's nothing else [to be said]. We already know how key Leo is. He's a very important player for football."

While Messi may not leave the club, Laporta's comments increase the pressure on Bartomeu, who was the subject of an online campaign last week asking for him to resign.

Neymar, who left Barca for Paris Saint-Germain earlier this month, has also weighed in against the club's board, saying they do not deserve to be in charge.