The FIA has banned Ferrari from using their latest rear wing design on Saturday ahead of this Sunday's Spanish Grand Prix.
The Italian team were testing a number of car upgrades during Friday's practice sessions at the Circuit de Catalunya, but the sport's governing body deemed the new design to be in breach of the technical regulations.
The Maranello based team had tried to exploit an area in the rules which meant that they could raise the overall height of their rear wing - but the FIA technical delegate suggested that they had bent the rules a little too far.
"It's a very clever interpretation of the rules and we have got to decide whether it's a good interpretation of the rules." said Charlie Whiting.
The FIA's decision means that Ferrari has had to take the new wing design off its car for the final free practice session in Spain, and it has reverted to the specification of rear wing that it used at the Turkish Grand Prix.
Ferrari announced on twitter that both Spaniard Fernando Alonso and Brazilian Felipe Massa's cars had been fitted with the standard rear wing ahead of Saturday's practice session.
"The 150Â° Italias are fitted with a standard rear wing after the team was told that the solution tested yesterday could be declared illegal," read the statement.
"Other items tested yesterday have been fitted today so we hope we can see a progress in terms of performance."