The Mercedes Formula One team were ordered on Wednesday to appear before the sport's international tribunal for allegedly breaking the rules by testing during the season with their current car.
Formula One's governing body, the International Automobile Federation (FIA), said in a statement it had decided on the action after investigating the test conducted in Spain with tyre supplier Pirelli between May 15-17.
Ferrari, who conducted a similar 1,000 km test in Spain in April but with a 2011 car and test driver, faced no further action because they were not deemed to have contravened the regulations.
No time was set for the tribunal, which could impose stiff sanctions against Mercedes if they are found to have acted illegally.
