The Brawn GP, Toyota [Images] and Williams Formula One teams face an attempt to bar them from the Australian Grand Prix Thursday in a controversy that threatens to sour Sunday's season-opening race.

The governing International Automobile Federation (FIA) said Red Bull, Renault [Images] and Ferrari [Images] have lodged protests on grounds the rivals' cars did not comply with technical regulations.

Another protest by BMW-Sauber was ruled out on a technicality.

The FIA said representatives of the three teams have been invited to appear before the race stewards at the Albert Park circuit.

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.

"Sadly a lot of the column inches this weekend are going to be about controversy and it can easily become acrimonious," McLaren [Images] 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.

"It's a shame that this sporting occasion is going to have that controversy thrust upon it over the course of the weekend."

DECISION NEEDED

Whitmarsh said McLaren, the team of world champion Lewis Hamilton [Images] who are battling to get their own car up to speed after being off the pace in testing, also need a clarification.

"We have an underdeveloped car, we do not have sufficient aerodynamic downforce and we'd like to focus on rectifying that situation as quick as we can," said Whitmarsh.

"In order to do so it would be very handy if I could tell our aerodynamics team that these are the rules that prevail. And I can't actually do that today, which means that you've got a foot on the bank and a foot on the boat.

"Either the majority of the teams are going to have to change the design of their car or the minority are going to have to change theirs," he said.

Formula One's regulations have undergone dramatic change this season but there are grey areas.

Brawn, who are using the same Mercedes engines as McLaren, have alarmed rivals with the pace of their car that was designed over the past year-and-a-half by Honda before the Japanese manufacturer decided to quit in December.

Honda effectively wrote off last season to concentrate on producing a winning car for 2009 and poured money and resources, including the use of three wind tunnels, into the project.

Brawn's British driver Jenson Button [Images], who has become a favourite for Sunday's race, brushed off the dispute.

"It's not something I have any control over personally," he said. "It doesn't change anything for me. I can't do anything about it."

FIA President Max Mosley said last week that the row could rumble on for some time yet:

"Probably what will happen is that it will end up going to the stewards who will make a decision. That will almost certainly be appealed by whichever side is disadvantaged. And then that will go to our court of appeal and be hammered out."

• Formula One coverage