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.

Interview: Former F1 champion Sir Jackie Stewart

"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.

606: DEBATE I think the FIA is completely out of control and for me this devalues F1 more than the recent antics of teams and drivers Slip-Stream

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'.