Renault are the latest team to express doubts over the initial blueprint released by the FIA and FOM which sets out the vision for Formula 1 from 2021.
The 1.6 litre engines are set to stay, but the removal of the MGU-H in favour of a more powerful MGU-K will create another “arms race”, according to Renault.
“Despite maybe what FOM and FIA would say – what is put forward is a new engine,” Renault F1 managing director Cyril Abiteboul told Motorsport.com.
“It is a new engine with lots of gimmicks, but it is a new engine. And that is really for me the most fundamental element.
“We need to be extremely careful because each time we come up with a new regulation that will come up with a new product – new engine or new chassis – we all know what is the impact.
“It is going to open an arms race again, and it will open up the field once again.”
Mercedes boss Toto Wolff also agrees with Abiteboul that a brand-new engine has essentially been announced.
“When you look at the bullet points presented, it looks like no big change and is superficially similar, but there is massive change in there,” Wolff added to Motorsport.com.
“It is an all-new engines, with new harvesting and deployment strategies for energy.
“All of us accept that development costs and sound need to be tackled, but we shouldn’t be running away with creativity in coming up with new concepts, because it will trigger parallel development costs over the next three years.”