The debacle has been an unwelcome distraction since the beginning of the FIFA World Cup, with no appearance fees having been paid during the tournament.
However, Mahama has now spoken to the players to assure them that the issue will be resolved on Wednesday.
The African nation's government has promised to pre-finance the payments, which will be reimbursed when FIFA's prize money for participation in the competition is received.
A statement from the Ghana Football Association read: "We wish to assure the general public following President Mahama's intervention the Black Stars are in high spirits ahead of Thursday's match last Group G match against Portugal."
Ghana, third in Group G, have to win that fixture to have any hope of qualifying for the second round for the third time in a row.
