Ferrari are set to have an easy race next weekend as today World championship challengers Williams are racing to fix aerodynamics problems with their new car.

Technical director Patrick Head told reporters at the team's factory near Oxford on Wednesday that the FW25 was currently slower than expected.

"I am of the view that our car isn't performing well enough," he said.

"It's not going as well as we want it to and we recognise a few handling problems which we don't want to be there. We can measure a few aerodynamic characteristics which we think are driving these problems."

Williams finished overall runners-up in 2002 after taking just one win in a season dominated by Ferrari, who won 15 of the 17 races.

They, and Formula One's rulers who have changed the regulations to try and make the championship closer, had hoped the more adventurous new car would close the gap and take on Ferrari from the first race in Melbourne on March 9.

The car has a shorter wheel-base and Williams also say it is smaller and lighter.

World champion Michael Schumacher, however, was lapping in the new Ferrari F2003-GA more than three seconds quicker than Colombian Juan Pablo Montoya in the Williams at the Jerez circuit in southern Spain on Tuesday.