Alex Fontana, Carlos Sainz, Kevin Korjus and Patrick Kujala have been handed ten-place grid penalties for the opening race of the GP3 season.
The quartet were all deemed by the stewards to have ignored waved yellow flags during the free practice session at Barcelona.
Yellow flags were brought out during the early stages of the 45-minute session when Josh Webster and then Kujala went off track.
Fontana went on to post the third fastest time for Jenzer Motorsport. MW Arden driver Sainz was 13th, with Koiranen GP duo Korjus and Kujala 22nd and 26th respectively.