Newey wants engine decision soon

"Luckily with the V8 engines the installation of engines is fairly similar," Newey told a news conference at Monza. "We have been able to wait a little bit longer but we will need to know soon the final decision."

Red Bull are on the first of a two-year deal to use Ferrari engines, but the outfit are in talks with Renault over a possible supply for the 2007 season.

Red Bull are aiming to convince Ferrari to switch their supply to sister team Toro Rosso who, according to Red Bull owner Dietrich Mateschitz, has reached a deal to end their contract with current suppliers Cosworth early.

Christian Horner, Red Bull's sporting director, said it would make sense for Ferrari to supply to Toro Rosso.

"Basically a lot has been said and discussed about engines," said Horner. "We have a contract with Ferrari for 2007 which we entered into in May last year.

"There is another team that Red Bull has interest in now, an Italian team, it would make sense for that team with an Italian team and Italian driver... there is synergy there.

"Basically, we entered into a two-year agreement with Ferrari. If that agreement has that possibility of being assigned it would be investigated and it would pave the way for a different engine to be put into the back of a Red Bull Racing car next year."