The most obvious problem is KERS, with Germany's Auto Motor und Sport confirming that it was taken off the RB7 due to reliability problems in Melbourne.

The main issue with the team's energy-recovery system - which ran apparently without problem in the initial Friday session at Sepang - is cooling, with the batteries running hot.

Another potential concern with the RB7 is its fuel tank size, after Mark Webber immediately pulled over with low fuel in Melbourne and Vettel also conserved fuel on his run to victory.

Another sign that Adrian Newey has pushed the envelope with tank size this year is that Webber and Vettel did only a single lap on the way to the grid before the race in Melbourne.

There are also rumblings about the RB7's high tire wear, with Lewis Hamilton significantly closing the gap prior to the first pitstop in Australia due to Vettel running out of grip.

"Melbourne has never been a good indicator of the balance of power," Michael Schumacher said at Sepang ahead of the second race of the season.

"So we have to wait.  It is clear that Red Bull have the best car but the question is how much better."