Ferrari, Renault and Red Bull Racing have lodged protests about the legality of diffusers on rival cars, after BMW Sauber's similar complaint was rejected on a technicality.
Following intense speculation in the build-up to the race about protests being lodged, an FIA statement on Thursday night confirmed that Ferrari, Renault and Red Bull Racing have lodged formal complaints with the race stewards.
The protests are against Brawn GP, Toyota and Williams over the design of their diffusers, which teams claim exploits a loophole in the regulations to extend the diffuser higher than some believe is legal.
BMW Sauber had also joined in the complaints but it is understood that the team failed to complete the necessary paperwork in time, so the stewards rejected its protest.
The FIA stewards have called representatives of Williams, Toyota and Brawn GP to a meeting in race control to discuss the situation. Following that meeting, it is expected they will make a ruling on the matter on Thursday night.
Whatever the outcome of that stewards' decision, the losing party is expected to appeal the matter - which would force an International Court of Appeal hearing to take place in the next few weeks.
Toyota president John Howett said on Thursday night that he remained confident the stewards would confirm that the diffuser designs were legal.
"As far as I know in motor racing anyone is allowed to protest and I don't have an issue with that," said Howett. "It is in the sporting regulations, it is in the main regulations and as far as we are concerned we have studied the regulations in detail and we are very confident that we have interpreted them correctly."We've used the consultation process with the FIA technical department and we are satisfied that they have verified our interpretation. Now we wait to see what the stewards or subsequent court may decide."