The cost of the fuel was raised by one of the engine manufacturers at a recent Formula One commission meeting that included team bosses and major stakeholders.

"What makes it so expensive is that the whole supply chain and energy contribution needs to be green," Wolff told reporters at the Miami Grand Prix, round six of the season.

"To achieve all of that, you need a certain specification of ingredients that is very expensive. And it’s coming in much more expensive than anyone thought.

"So we need to look at whether there's anything we can tweak to bring the per-litre price down."

Wolff said Mercedes' fuel partner Petronas was fully committed technically but looking into whether a regulation change could make sustainable fuel also more financially sustainable.

Red Bull boss Christian Horner agreed there were a lot of development costs involved, but said it was not a significant issue for his team.

"Maybe a certain bracket should be introduced going forward. But fuel is potentially one of the bigger performance differentiators. The fuel companies seem very engaged in that," he added.

--Reuters--