Talks over fresh terms for the Argentina international have been ongoing since the start of the year, leading to suggestions that other clubs - namely Pep Guardiola's Manchester City - could be ready to pounce in the summer for a world-record fee.
Messi has still yet to formally agree a new deal in Catalonia, however, with his current contract due to expire at the end of next season, but Fernandez is confident that an announcement will soon be made as the four-time Ballon d'Or winner is "happy in Barcelona".
"Messi will renew," he told Cadena SER. "I have always said Leo is happy in Barcelona. He is very happy here, he is in a magnificent team. I have no doubt that he will renew."