Coulthard is on a one-year deal at Red Bull

Team boss Christian Horner said reports that Vitantonio Liuzzi and Christian Klien would drive for the team in 2006 were "totally inaccurate".

"David's doing a great job for the team," said Horner.

"It's far too early to even contemplate next year, and we won't until the latter part of the summer, but the team's very happy with David."

Coulthard, who signed a one-year deal with Red Bull after leaving McLaren at the end of last season, has scored points in all three races so far this season.

The 34-year-old Scot's sixth place in Malaysia made him the highest points-scoring British driver in Formula One history.

David has nothing to prove Red Bull team boss Christian Horner

"The situation with David is that he's one of the top drivers in Formula One, we're fortunate to have him and he's a great benchmark for the other two," said Horner.

"They've learnt immeasurably from him and we've got a great balance in the team of youth and experience and we're very comfortable with that.

"We had dinner with David on Monday and Mr Mateschitz [Red Bull's owner] reaffirmed how content he was with David then.

"He's the stability in terms of development and continuity. He has nothing to prove."

Italian driver Liuzzi will make his F1 debut in Sunday's San Marino Grand Prix, replacing Austrian team-mate Klien.

"It could well happen two or three times in the year," said Horner of the swap, which was arranged before the season started.

"Both are talented young drivers and we have agreements that stated they will both race this year.

"It's the only way for us to truly evaluate a driver under the pressure of racing, which is what its all about.