Ferrari's rivals remain unsatisfied with the way an investigation into the legality of the Italian team's engine was handled over the winter.
Responding to concerns from other teams last year, F1's governing body, the FIA, conducted an investigation into Ferrari's power unit over the winter, eventually reaching a confidential settlement with the team.
With no further information on what the investigation had found, seven of F1's ten teams accused the governing body of a lack of transparency, resulting in the FIA admitting it had held doubts over the legality of Ferrari's power unit, but was not convinced it would reach a conclusive outcome by taking the issue further.