The new Brawn GP BGP001 has joined Williams' FW31 and the Toyota TF109 on the list of Formula 1 cars with controversial diffusers in 2009, it has emerged - with little hope of resolving the dispute before the curtain-raising Australian Grand Prix in Melbourne at the end of the month.

Cologne-based publication Express has reported that the ex-Honda machine has taken Williams and Toyota's interpretation of the diffuser even further, to the extent that it 'does not conform to the regulations'. The Mercedes-powered challenger has stunned observers with its scintillating raw pace and consistency in testing at Barcelona and Jerez over the past two weeks, regularly lapping up to a second quicker than any of the opposition despite the team having looked for much of the winter like it was facing extinction.

According to the German newspaper, the BGP001 design effectively links the floor of the car with the diffuser in a curved manner, thereby significantly increasing rear downforce.

Rivals have accused the three teams in question of going over the maximum permitted ride height for the structure - but no official protest will be allowed until all of the cars arrive Down Under for the first grand prix of the season in just under two weeks' time, reveals

Renault F1 managing director Flavio Briatore has already suggested that 'it seems that there are two rules' and that some teams have unfairly exploited the ambiguity of the regulations to gain an advantage [see separate story - click here]. Ferrari team principal Stefano Domenicali has since added his voice to that concern, claiming that whilst some teams applied the 2009 rules 'to the letter', others elected to follow 'a different approach'.

"We think that we've applied the modified regulations," the Italian explained, "together with the FIA - to the letter. It might be that others took a different approach. The FIA has to dissipate any doubt; let's hope they'll do it fast and clear."

Whilst some teams are up in arms about the perceived discrepancy, the FIA has already declared Toyota and Williams' designs legal and not in contravention of the regulations, with president Max Mosley underlining: "The current FIA view is that Williams and Toyota have been clever and found a loophole in the rules. It's probably wrong, but they've exploited the wording of the rules in a clever way.

"Somebody may challenge it and then the stewards could take another view. The view of our technical people is that it's okay; we'll wait and see if someone challenges it."