Sky Sports News reports that Messi wants his lawyers present too, so all parties can find a solution to the impasse over his contract.
Manchester City are favourites to sign Messi after his contract with Barca expires, but Paris Saint-Germain and Inter Milan are closely monitoring the situation.
The 33-year-old is trying to activate an exit clause in his current deal that allows him walk away from the Camp Nou for free.
However, Barca feel the clause expired in June, although Messi feels the season ended in August this year, due to the COVID-19 break.
The contract has one more year to run and the Spanish club will be looking to get some money from any transfer.