The 31-year-old moved to the Spanish capital in the summer of 2009 from AC Milan in a then world record £56 million deal, but he has since failed to play at the standard which saw him awarded the 2007 Ballon d'Or.
With the Brazilian star having repeatedly stated his intention to remain with los Blancos because he wants to still prove himself, Zico believes it would be best if he returned to his homeland.
"Kaka's best option would be joining a different red and black team, the one from Brazil and to be more specific, the one from Rio de Janeiro, Flamengo," Zico told Esporte Interativo.
"Kaka still wants to prove he can be more useful at Real Madrid than he currently is, despite all his difficulties there."I talked with him about it and he smiled, it would be very good for him and for the national team if he played in the Brazilian national league.
"I'm not saying this as a Flamengo fan, I'm saying what I think, if Kaka wants to be a protagonist again."
In his four seasons with Real Madrid, Kaka has scored 28 goals and provided 37 assists in 117 matches.