Norbert Haug has revealed he is not in favour of allowing teams to field three cars per Grand Prix.
Ferrari, whose president Luca di Montezemolo is highly critical of the uncompetitive small teams, is pushing hard for the rule change.
But Haug, Mercedes' competition director, is quoted by f1today.nl at the Valencia test: "Three cars per team is not something we support.
"It would be disastrous for the small teams so we see the current situation as much healthier.
"If we can avoid having three cars per team, we certainly will do so," added the German.