F1 teams furious over bodywork

The British team said the Brawn GP, Toyota and Williams cars run with rear diffusers, underbody sections to aid air flow, which are contrary to the rules. Ferrari and Renault have also expressed their unhappiness.

"It's illegal," Red Bull adviser Helmut Marko said. "We'll make a protest on Thursday if the component isn't modified to conform to the regulations, because that diffuser guarantees a five-tenths (of a second) advantage per lap. "Seven teams are certain it's illegal."

The controversy surfaced during pre-season testing and intensified when the new Brawn GP cars proved fastest, with Britain's Jenson Button installed as this weekend's favorite by local bookmakers.

The ruling International Automobile Federation (FIA) has declined to intervene with president Max Mosley reportedly saying the decision rests with race stewards in Melbourne.

But Red Bull said it will force the issue to ensure the three teams comply with the standard design used by the other teams. Renault boss Flavio Briatore also said the design should have been declared illegal.

"It looks like there are two sets of regulations: the one that allows some teams to have the diffuser built in a certain way that is forbidden to others because it's considered illegal," Briatore said.

"At least three teams don't respect the regulations. It is not what we expected. We want black and white rules for everybody."

Ferrari team principal Stefano Domenicali said: "We are convinced that certain interpretations that have been applied do not correspond to the nature of the rules. There needs to be a great sense of responsibility on everyone's part. I hope this issue can be resolved quickly."

Mosley said the matter might eventually be settled in the FIA Court of Appeal.

"It's a very clever device and you can make a good case for saying it's legal and a very good case for saying that it's illegal," he said.