The fourth and final group test of the F1 pre-season will take place over five days, rather than four, after the teams failed to reach agreement on which days should be used.

The test, originally scheduled for Bahrain International Circuit later this week, has been moved back to Spain in light of the civil unrest that led to the cancellation of both the season-opening Bahrain Grand Prix and the accompanying GP2 Asia Series but, so far, the twelve teams have not agreed to run on the four days initially slated for the session.

With extra time to fill before racing gets underway in Australia, the test was moved back a week, to 8-11 March, before being pushed back a further 24 hours to start on Wednesday 9 March. That late tweak, however, has not found favour with the entire field, with nine of the twelve competing teams insisting that they will be sticking with the original schedule and only Williams, Ferrari and Mercedes confirming that they will accept the later days.

In order to get around the confusion, the Circuit de Catalunya has announced that it will provide access to the circuit for all five possible days, extending the test from 7-12 March, although the teams will only be allowed to participate on four of those, as per the regulations. The Australian Grand Prix runs from 25-27 March, with a two-week gap to the Malaysia-China double-header that follows.

The Spanish Grand Prix venue has already played host to the F1 circus this winter, with Ferrari's Felipe Massa topping the combined times at the third group test. The Brazilian, who is looking to bounce back and take the fight to Ferrari team-mate Fernando Alonso in 2011, headed a top five completed by Nico Rosberg (Mercedes GP), Sebastian Vettel and Mark Webber (both Red Bull) and Lotus-Renault's Vitaly Petrov.