Messi's current contract at the Nou Camp expires in 2018 and the Catalan giants have made extending the Argentine star's deal their biggest priority.
Now, Spanish media are reporting agreement has been reached with Mundo Deportivo saying Messi's father has accepted Barcelona's proposal to extend the deal.
Messi has endured a difficult summer, dramatically retiring from international football as Argentina were beaten in the final of the Copa America and then being sentenced to 21 months in prison for tax fraud - a punishment he is unlikely to serve.
Barcelona have stood by their star man throughout those difficulties, the club starting a #WeAreAllLeoMessi social media campaign in light of him receiving a supposed jail term.
Since Argentina's final defeat by Chile on penalties, Messi has kept a low profile but as the club's highest-paid player with two years remaining on his current contract, his importance is undeniable.
A four-time winner of the Ballon d'Or, Messi will be hoping to help Barcelona wrestle back the Champions League crown from bitter rivals Real Madrid next season.
'We need to renew the contract of Messi, as well as lots of other players that we want to stay,' Barcelona president Josep Maria Bartomeu said last month.
Barcelona have already added to their squad this summer with the signings of defenders Lucas Digne and Samuel Umtiti while they are also close to securing a deal for young Atletico Madrid forward Luciano Vietto.
But retaining stars such as Messi - Javier Mascherano's deal also expires in 2018 - is also high on the club's agenda.
Messi's partnership with Neymar and Luis Suarez is at the heart of Barcelona's success, with Brazilian Neymar having committed to the club on a fresh five-year deal this month.
Barcelona's new 155 million euros sponsorship deal with Nike begins in 2018 and the cash-rich status of the club means they're able to ward off interest from other clubs.
Messi has been occasionally linked with moves to the Premier League, but it remains likely he'll see out his career in Spain.
'We've had another record revenue of 670million euros (£560), pending an audit, which will be presented at the end of July,' Bartomeu added.
'That's 62million euros (£52m) more than last year. We've reduced our debt by 40million (£33m) and it's now at 280million euros (£234).'