Melbourne- Race stewards turned down protests filed by several Formula One teams Thursday against rivals Brawn GP, Williams and Toyota over their cars three days ahead of the Australian Grand Prix.

Ferrari, BMW-Sauber, Renault and Red Bull complained the three teams' diffusers - a part of the car which improves its aerodynamic performance - gives them an unfair advantage.

The protest, which was lodged after stewards in Melbourne said the cars conformed with Formula One's rules, was turned down by the three race commissioners.

The teams now intend to appeal the decision to motorsport's ruling body FIA, which would likely not hear the case until after the second race of the season in Malaysia on April 5.

It remains unclear whether this would make the results of the first two races conditional on the outcome of that appeal.

The dispute centres around the rear diffusers, a part of the bodywork between the rear wheels and under the rear wing which disperses air from under the car.

It is claimed the designs of the Brawn GP, Williams and Toyota cars will give them a speed advantage of up to 0.5 seconds a lap as a result of the extra downforce which boosts a cars grip on the track.

New regulations limit the size of the diffusers but the three teams have found a potential loophole in the rules by designing the rear bodywork to effectively act as part of the diffuser, increasing its size.

"It's nothing personal against the teams, it's simply looking to clarify regulations - our interpretations and others have been different," said Red Bull team principal Christian Horner.

"Our purpose in all of this is to establish the clarity of the regulation, because it has significant impact on how we channel our development."

BMW motorsport director Mario Theissen said his BMW-Sauber team understood the rules differently than Brawn GP, Williams and Toyota, who will now run with the controversial set-up at Albert Park.

"We interpret the rules differently and don't see the leeway which the three teams are using.

"If this is ruled to be legal there will be much more scope than has been made use of so far by the three teams."

It would lead to new and expensive efforts by teams to redesign their cars to give them a similar aerodynamics advantage, he added.

The BMW protest was later rejected on a formality but the other teams' protests were accepted.

McLaren-Mercedes didn't lodge an official protest but Mercedes motorsport director Norbert Haug commented that the issue "has to be clearly regulated."