During the season opener in Bahrain last weekend, we reported that McLaren had been told that the diffuser fitted to its MP4-25 may not reappear in Melbourne.

McLaren had reportedly aerodynamically exploited the hole for the external engine starter, making it much bigger than necessary and thereby gaining another diffuser level.

It was said the British team agreed to revise the design for Melbourne.

Spain's El Pais newspaper said Renault and Mercedes will also have to modify their diffusers for the same reason ahead of round two of the 2010 world championship.

Rumors also suggest that one or two other cars may also be the subject of FIA technical delegate Charlie Whiting's concerns.

It is believed these teams exploited the fact that while FIA rules allow a hole in the diffuser big enough for an external starter, the regulations do not set a maximum size for the starter probe itself.

Red Bull designer Adrian Newey admitted he suspected at least two teams of pushing the rules.

"I will not say names, only that Ferrari is not among them," the Briton is quoted as saying.