Red Bull's Helmut Marko has called Mercedes motorsport chief Toto Wolff "paranoid", saying he fears Mercedes will lose its superiority over the Formula 1 field if the sport adopts proposed rule changes next year.
F1 is set to agree new rules which will dramatically change the look and performance of the cars in 2017.
However the rules, which will be finalised on April 30, have come up against some criticism, particularly from Wolff who recently suggested they should be abandoned as they were no longer needed.
"The longer you keep regulations stable the more the performance is going to converge between everybody," said Wolff. "And this is exactly what is happening now.
"The engines are converging. The teams are converging. The gains we are making are smaller as the curve flattens out, and the others are making bigger steps. So I think we have an ideal situation now with great racing."
Marko disagrees and believes Wolff's comments are aimed at derailing the changes to protect Mercedes' dominance.
"Except for Toto and the teams that must follow him due to their engine contracts, everyone is for a change. Even [Ferrari chairman] Sergio Marchionne agrees," he told Motorsport Magazin.
"Only Herr Wolff has this paranoid fear that Mercedes will lose its superiority if you change even the smallest thing on the engine or chassis," he added. "He is doing everything he can to prevent any change."