Messi, whose current deal was due to expire in 12 months, sees his release clause rise to €300 million and the deal will be signed in the coming weeks, when he returns to the team for preseason training.

It will be the ninth professional contract the Argentina international has signed since he moved to the Camp Nou and commits him to the club until he is 34.

There had been some concern over his future as Barca allowed him to edge closer to the end of his current deal.

At various points throughout the last year he was linked with a move away from Catalonia, with a number of clubs reported to be monitoring the situation, including Manchester City.

However, Barca always remained optimistic that he would renew, telling ESPN FC in November that they were confident he would pen a new deal.

President Josep Maria Bartomeu personally took charge of the negotiations, working with Messi's father, Jorge, to reach an agreement.

Messi joined Barca in 2001 from Newell's Old Boys, made his first team debut against Espanyol in 2004 and has since gone on to win 30 trophies with the club, including eight La Ligas and four Champions Leagues.

In addition, he has become the top scorer in the club's history (507) and in La Liga history (349) and has been named the world's best player on five separate occasions.

The contract renewal completes a busy summer for Messi, who turned 30 in June and wed long-term partner Antonela Roccuzzo in their native Rosario last week.

Barca have now tied down all three members of their attack to new deals.

Messi follows Neymar and Luis Suarez in committing his future to the club, who begin the new season under the guidance of coach Ernesto Valverde after Luis Enrique decided to step down after three years in charge.