It seems nine of the 12 teams have opted to stick with the original dates, 8-11th March, for the final pre-season test in Barcelona, whilst the remaining three will test between the 9-12th.
This effectively means the test becomes a five-day affair, though teams are limited to just four days running.
Williams, Mercedes and Ferrari have all confirmed that they will run during the later dates, though it is unconfirmed whether any of the remaining teams will follow suit.
Sauber and Force India have both confirmed their intention to stick with the original dates. The latter stated the reason to run earlier meant they could concentrate on getting their freight to Australia for the first race on March 27th.
Hispania are also expected to run during the earlier dates and will debut their new F111 on-track for the first time.
