The contract would be for five years with an option for renewal each of the next four years Barcelona-based sports daily Mundo Deportivo said Thursday.
That would run to 2014 -- when Ronaldinho would be 34 -- at which point he would then represent Barcelona in an ambassadorial role the paper added.
Ronaldinho whose current contract expires in 2008 would earn $152 million the paper said.
Barcelona is trying to extend the contracts of key players who helped it win the Spanish league title for the first time in six years. It has also sought to improve the deals of its young prospects.
Samuel Eto'o Deco and Xavi Hernandez together with reserves Lionel Messi and Damia Albelda have all agreed extensions until 2010 while coach Frank Rijkaard and captain Carles Puyol are expected to do so soon.
Ronaldinho who helped Brazil win the Confederations Cup on Wednesday joined Barcelona from Paris Saint-Germain for $36.3 million in 2003.
He is the latest in a line of talented Brazilians to play for the club -- after Romario Ronaldo and Rivaldo.
Ronaldinho's spectacular displays in his first season made him Barca's major asset and gained him recognition as one of the world's best players. The club responded by granting him a salary rise and set his buyout clause at $181 million.
In his second season the forward's form was less spectacular but he still won FIFA's world player of the year award in December.