Mercedes team principal Toto Wolff says it would be "madness" to push through major changes to Formula One's engine regulations in 2021 as it would require existing manufacturers to develop two power units in tandem.

F1's next engine formula is at the centre of plans to provide closer racing and a more level playing field among teams in 2021.

Earlier this year, F1 proposed a change in regulations that would keep the current V6 engine architecture but remove the complicated MGU-H from the hybrid system. The plan also permitted an increase in the fuel allowance to help the engines rev higher and sound better, while an upgraded MGU-K was tabled to ensure they remained both powerful and road relevant.

Mercedes, Ferrari and Renault initially raised concerns about the proposed changes, but it appeared as though an agreement had been reached in Monaco to ditch the MGU-H. Part of the reason for the change in stance was the belief that it would lower the barrier to entry for new manufacturers, with Porsche involved in the talks from the beginning, but it now appears as though no new manufacturers are willing to commit.

Toto Wolff is skeptical about the next set of engine regulations. Eric Alonso/Action Plus via Getty Images

A detailed version of the of 2021 regulations was scheduled to be released at the end of June but a subsequent meeting of F1's Strategy Group stalled an agreement. With no firm commitments from new manufacturers on the table for 2021, Wolff has now questioned why the regulations surrounding the MGU-H should be changed at all.

"I think we have made our standpoint pretty clear that we think, for the sport, the best thing would be not to change a lot," he said during an AMG media event at Mercedes' headquarters in Stuttgart. "Leave it like it is so that the performances of the various engine suppliers converge.

"But then you need to take into account the sound debate, fuel saving, and maybe we can tweak it a little bit, add a little bit more revs, give more fuel allowance, and I think that would be perfectly enough to have good racing."

Given the lead time required for engine design, Wolff said F1 would have to finalise the new regulations "soon" if it wants a major change for 2021. But he also warned that it would result in a dramatic escalation in costs for existing manufacturers as they develop their current power units and the new one in tandem.

"The risk with knowing soon is that then everybody would start as early as now and develop two engines in parallel, which would be madness in my opinion."