But the deal he wants would see him paid £18m a year AFTER tax, meaning a weekly wage of £600,000 before deductions.
He is currently earning over £14m a year net in La Liga and has a buy-out clause in excess of £175m.
Messi has been with Barcelona since 2001 and has previously said he wants to retire with the Catalan club.
But a probe into an alleged £3m tax fraud, said to have been organised by his father Jorge, has soured Messi’s love affair with Spain.
Last month a judge ruled Messi and his father should stand trial on tax fraud charges.
Prosecutors allege Jorge avoided paying tax on his son’s earnings by using offshore companies in Belize and Uruguay from 2007 to 2009.
Messi’s lawyers argued the player had no knowledge of his father’s actions, but the judge decided: “There are rational signs that the criminality was committed by both accused parties.”
Both Messi and his father deny wrongdoing.