After a promising birth for the RB5, the 2009 Red Bull car is reportedly now facing a midfield finish at next weekend's Australian grand prix.

At its early tests, the Adrian Newey-penned car looked set to join Ferrari, BMW, Toyota and Renault at the closely-fought front of this season's grid.

But as the reliability of the Renault-powered car improved, the development of its sheer pace was not as good, culminating in a mediocre showing at its last pre-Melbourne outing in Barcelona last week.

Among the most concerned is Australian driver Mark Webber, who has not looked a match this winter for his young teammate Sebastian Vettel.

After Barcelona, Webber told Germany's Auto Motor und Sport: "The car did not feel bad, and that is the most alarming thing.

"The others have developed (their cars) better than we have," the 32-year-old added, admitting that the basic setup of the car suits Vettel's driving style better than his own.

Webber, who at Barcelona returned to the saddle of a bicycle and did a lap of the Spanish layout, insists that his recovering leg injury is not the cause for his struggle with the RB5.