Mercedes Motorsport boss Toto Wolff hasn't exactly given the proposals put forward for changes to the engines in 2021 a thumbs up, insisting nothing has yet been agreed between the FIA, Liberty Media and the manufacturers.

In a meeting of the Strategy Group on Tuesday, the governing body released the initial ideas put forward after a series of talks between the relevant parties with the aim of cheaper, simpler and noisier engines units, three of the main criticisms of the current hybrids.

More revs, no MGU-H but the retention of the same 1.6-litre V6 along with a more powerful KERS were the main takeaways, however, as would perhaps be expected for the team that has benefitted massively from the current power units, the Mercedes boss was cautious in his reaction.

"The concept sounds similar to what we have now but it means a completely new development that will mean we are working on two engines at the same time between 2018 and 2020," Wolff explained.

"It's a vision rather than a regulation and it's their vision rather than the manufacturers," he added. It is important to define all together what F1 should be in 2021, not just from the point of view of the engine.

"What we have is the starting point of a dialogue rather than something we have agreed to. Certain things are right, but it's not quite there."

The Austrian is also concerned that, though reducing costs in the long-term is the goal with the new engine rules, the period between now and when the new engines are introduced will require greater financial investment.

“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,” Wolff said.

That point also has the backing of one manufacturer that is more in favour than some of ending the current regulations and that's Renault, who has been third best behind Ferrari and Mercedes pretty since 2014.

“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," Managing Director of the Sport division Cyril Abiteboul stated.

“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.”