Rubens Barrichello has scolded suggestions that Brawn GP has pulled clear of the entire F1 field because the BGP001 is "illegal".

Up and down the recent Barcelona and Jerez test paddocks, it has been intimated that the former Honda might not only be running under the mandatory weight, but circumventing the regulations including in the area of the rear diffuser.

"You're asking are we legal? When someone is behind it is easier to say your rivals are against the rules than to do better work.

"Our team is very much within the regulations," the Brazilian veteran insisted to Spain's Marca sports newspaper.

The test pace of the 36-year-old driver, and his British teammate Jenson Button, has led even cynical observers to contemplate that a winning Brawn could come close to lapping its nearest competitor in Melbourne next Sunday.

Barrichello said: "In Australia I believe we will be within the three strongest teams, these being Ferrari, Toyota and BMW, with (Renault's) Alonso who could be a surprise."

The handsome Brackley built chassis has received much of the credit for the incredible boost in form compared with the car's predecessor, but the move from an underpowered Honda V8 to Mercedes-Benz's engine should not be forgotten.

"It is very manageable, very powerful," Barrichello affirmed, "but I believe that the greatest secret is the team; the quality has always been there."

He is openly excited about the now-looming start to the 2009 season.

"I left Ferrari to find a team that would give me equal conditions, more freedom, not having to race for Michael (Schumacher), and now I have a strong car as well," said Barrichello.