Sir Jackie Stewart on Saturday admitted he has a "very, very big" safety concern about F1's revolutionary new era.
"I see a very, very big problem," the F1 legend told German newspaper Die Welt in Melbourne.
Indeed, it is believed the very sort of concern raised by Jackie Stewart, F1's safety-pioneering driver of the 70s and a triple world champion, was also raised by experienced current drivers including Jenson Button in the FIA briefing in Australia.
The worry is that the new 100 kilogram per driver race fuel limit could mean some cars are aggressively saving fuel at the very same time as others are still racing flat-out.
"Drivers who are six seconds slower than the fastest cars is a huge safety risk," 74-year-old Stewart said.
"And when you're talking about safety in formula one, it is the question of life and death," the Scot added.
"If I understand the problem, I cannot understand that others seem to have thought so little about it," he said.