Sir Jackie Stewart has accused the FIA of having a "big brother attitude" in its handling of the title race between Fernando Alonso and Lewis Hamilton.
Hamilton (l) has a four-point lead over Alonso with one race left
F1's governing body has appointed a special scrutineer to ensure McLaren give equal treatment to their drivers in the decisive race at Interlagos.
"It's a dangerous precedent," Stewart told BBC Sport. "The FIA is paid to govern the sport not manage the teams."
But president Max Mosley said the FIA is simply ensuring rules are respected.
"It is not the role of the FIA to court popularity by supporting one party or the other," Mosley said in a statement.
"It is the role of the FIA to ensure that the rules of the sport are respected and that fairness is applied consistently for all competitors."
Alonso's relationship with McLaren has become increasingly fractious during the season, leading the Spanish Motorsport Federation to voice concerns to the FIA that the Spaniard might not receive the same treatment as Hamilton in Sunday's final race.
Hamilton goes into that race with a four-point lead over the defending champion.
Three-times world champion Stewart believes it should be up to McLaren how they treat their drivers.
"I don't know what the governing body is about on this," he said.
"These teams are private enterprises. They pay an entry licence fee of considerable amounts of money for the FIA to govern the sport.
"It is not a governing body's prerogative to start saying 'you will do this in your team under our direction'.
"So in my view it as an error. It's a big brother type of attitude and I don't think that's the way to go."