PT leader Jose Genoino said Cardoso was "jealous" of the success President Luiz Inacio Lula da Silva has had since assuming office in January 2003 and laying the foundation for another run at the presidency in 2006.
Genoino, in a statement, said the ex-president was "consumed with resentment and jealous of the accomplishments of the Lula administration."
Cardoso -- whose eight-year, two-term administration was characterized as center-right -- has often spoken publicly against the leftist Lula and his policies, despite the fact the current president's conservative economic policies are similar to his own.
The former president denies he is interested in challenging Lula for Brazil's highest office next year.
2014: The Year in Music [PHOTOS]