The experienced midfielder, formerly with Barcelona, has told his country's top prospects to embark on European challenges as it will be the only way for them to blossom
The Santos pair have been strongly linked with clubs in Europe after an impressive season which saw the club lift the Copa Libertadores trophy.
Real Madrid and Barcelona have been suggested as Neymar's closest suitors, while AC Milan and Paris Saint-Germain have been credited with an interest in Ganso.
And Rivaldo, who enjoyed some solid success in Europe, especially at Barcelona, has indicated that the pair would do well to move quickly in order to raise their credentials.
"I think Neymar and Ganso need to leave as soon as possible. Same thing goes for [Sao Paulo's] Lucas," Rivaldo is quoted as saying by Lancenet.
"They need to be known worldwide and earn respect out there. It is not the same thing as playing here, in Brazil.
"I believe they have to leave, so that everyone can know them in two years, so that at the 2014 World Cup players will think twice before going out on them. They need to have experience, to play against players they will be pitted against at the World Cup."
The 39-year-old added that he is positive both Neymar and Ganso will become big hits in Europe, saying: "They have everything to be protagonists, they have a lot of talent. If they show 80 per cent of what they have shown here, they will be contenders for the best player of the world [honour]."