Renault has hit out at the FIA's decision to approve the radical F-duct vent system on the McLaren that has caused controversy in the build-up to the Bahrain Grand Prix.
The FIA has given the green light to the complex McLaren design concept, which sees the drivers close off a vent in their cockpit to help stall the rear wing for extra straight-line speed, even though some outfits feel it is breaching regulations.
Although Red Bull Racing has been the main critic of it so far, Renault has now spoken out and hit out at the FIA's stance - which it fears will spark a development arms race in Formula 1.
Renault managing director Bob Bell told the BBC: "It is fundamentally clear that the McLaren wing design is totally illegal - and they have driven a cart horse through the sprit of the rules and regulations.
"They have opened up another arms race; it's going to cost everybody a lot of money. The governing body needs to be a lot stronger with these things."
He added: "I think that it is ridiculous in this era where we are all trying to save money. We are restricted by the number of people that we can bring to the track, with mechanics working ridiculous hours at night to prepare the car.
"Now we have just opened another arms race that will cost us all a lot of money. It's just a nonsense. I think the governing body needs to be more responsible in decisions like this."
Despite his unhappiness about the matter, Bell said it was unclear if his outfit - or another rival - would consider a protest against the McLaren.
"I honestly couldn't comment on that at this stage," he said. "It's obviously not out of the question that any team could protest at this stage."