The Brawn GP, Toyota and Williams Formula One teams have been cleared by stewards to race in Sunday’s season-opening Australian Grand Prix after protests by three rival teams over the design of their rear diffusers were rejected.

Red Bull, Renault and Ferrari had lodged protests on grounds the rivals’ cars did not comply with technical regulations. The three will appeal the protest’s rejection.

The new Brawn GP team, who have been comfortably quickest in pre-season testing, and the other two teams have been using innovative but contentious rear diffusers – a key part that governs the quick and smooth flow of air under the car to increase downforce.

Rivals argue the cars are illegal in a dispute that has been simmering for weeks. All this follows the controversy over this season’s points system.

“Sadly a lot of the column inches this weekend are going to be about controversy and it can easily become acrimonious,” McLaren team principal Martin Whitmarsh told reporters before the protests were lodged.

“That’s the way of Formula One, to sometimes stumble across into a very acrimonious environment. In defence of everyone, I don’t think anyone has set out deliberately to cheat here.”

PHOTO: BMW Sauber driver Nick Heidfeld of Germany plays with kangaroos at Melbourne Zoo ahead of this weekend’s Australian Grand Prix, March 25, 2009. REUTERS/Mick Tsikas