Renault boss Flavio Briatore claims that three teams are breaking the rules with their diffuser designs.
His claim follows FIA President Max Mosley's statement last month that the diffusers on the Toyota and Williams did not break the rules even though it had been suggested they breached the limit with regards maximum height.
Mosley said the two teams had been "innovative" and had not broken the rules, it was subsequently reported that a third team was attempting to copy the design.
However, speaking to Gazzetta dello Sport, Briatore is clearly unhappy claiming that there is one rule for some and another for others.
"It seems that there are two rules," said the Italian, "one that allows some teams to have a diffuser done in a certain way, while for the others it is banned because it is considered illegal.
"It is not what we expected," he added. "We want black and white rules for everyone."
In pre-season testing pretty much anything is allowed, it is only when the cars turn up in Melbourne for the Australian Grand Prix that the FIA's officials will pay close attention to the diffusers. However, with two weeks to go, Briatore is warning that he may lodge an official protest.
"We will see," he said. "I am sorry because the spirit of the rules has not been respected by three teams."
The Italian has also admitted to being frustrated at the fact that some teams will run their KERS devices in Melbourne while others will not.