LONDON -- Formula One champions Ferrari have suggested they could lodge protests over several of this season's races after accusing rivals of using illegal tires.

Technical director Ross Brawn, in an interview with Autosport magazine on Thursday, said tire manufacturer Michelin had broken the rules for some time and Ferrari is investigating the situation.

Such action could mean the championship, on a knife-edge with Michael Schumacher one point clear of Colombian Juan Pablo Montoya with three races to go, is decided in the appeal courts rather than on the track.

"Measurements were taken after the Hungarian race that clearly showed that there were tires above the legal limit and we've got to see what develops because we're not happy with that situation," Brawn said.

"There is a facility within the FIA regulations to investigate any matter if previously unknown information becomes available.

"It's not what we want but Ferrari are very angry and frustrated as it is now clear that a large number of the Michelin teams were running illegal tires for a considerable amount of time -- and we don't know for how long yet."

Article 179b of the International Sporting Code allows a review of events if "a new element" is discovered.

Ferrari and tire supplier Bridgestone say Michelin have built tires that pass pre-race scrutineering but then change under race conditions to allow more tread to have contact with the road.

Michelin say their tires are legal. Autosport said the design in question had been used since the San Marino Grand Prix in April, fourth round of the championship.

The governing International Automobile Federation (FIA) has said there will be post-race checks, starting with Ferrari's home Italian Grand Prix at Monza next week.

Brawn dismissed suggestions that the FIA's move was damaging to the sport.

The top three drivers are split by two points, with McLaren's Kimi Raikkonen two behind Schumacher, while Williams are eight points clear in the constructors' championship.

The last Hungarian Grand Prix was won by Renault's Michelin-shod Spaniard Fernando Alonso, who lapped Schumacher.

"This was an attempt by Michelin to circumnavigate the regulations," Brawn said of the tire furore.

"It would be wrong if a car won the championship which had been blatantly using illegal tires. That is not right.

"...It devalues the competition and we must not allow people to win championships when they are contravening the regulations."