Brazil's national football coach Dunga said on Wednesday that he was considering suing his 1994 World Cup-winning teammate Romario over allegations of commercial interference in team selection.
In an interview with Italian newspaper La Gazzetta dello Sport on Tuesday, Romario, now a senator in Brazil, questioned whether Dunga was "involved in the Brazilian football confederation's dirty ways."
"I don't know if he is dirty, if he participates, but he is seeing everything," Romario said. "He is not blind or stupid."
The former Barcelona striker accused the CBF of allowing football agents to influence selection.
Brazil's technical director, Gilmar Rinaldi, was a player agent before becoming Dunga's right-hand man in July last year.
"Like all Brazilians, senator Romario has the right to criticize the choice of players selected to represent Brazil," Dunga said in a statement.
"But he doesn't have the right to say, without proof, that selection is based on non-technical criteria. I repudiate declarations from somebody who calls himself a friend, but isn't.
"Friendship requires respect, loyalty and utmost confidence in integrity. For that reason Romario has never been my friend and he is obligated to present the facts."
Dunga added that he and Rinaldi were "looking at the legal measures available with respect to the senator's declarations".
Romario has been an outspoken critic of the CBF and in May instigated a congressional investigation into allegations of corruption within the organization.