Dr Helmut Marko says F1 risks becoming a "bookkeeping world championship".

While confirmation of the 2021 rules has been delayed until October, it is believed the $175 million budget cap is definitely set in stone.

F1 CEO Chase Carey stands by the plan.

"It took us well over a year to discuss the issue of costs in detail," he told Austrian broadcaster Servus TV.

"I think the structure we have proposed will prove to be successful. Our sport is complicated, so we need rules to ensure that everything is done reliably."

But outspoken Red Bull official Dr Helmut Marko says the budget cap plan is inherently risky, amid a sport that many think is already overregulated.

"In the worst case scenario, we will have a bookkeeping world championship where disqualifications occur two months later," he said.

But Carey is determined.

"The plan is to run a test for 2020, which will be a learning process for all of us. We are under no illusions.

"My guess is that we will further refine the structure of the costs, but we need a starting point now. We want to change the sport so that better competition becomes possible," said the American.

Marko says the big teams are already looking into how to re-structure so that mass layoffs are minimised.

"We are looking for other areas of activity such as the development of the (Le Mans) hypercar," he said. "We may also use one wind tunnel for both of our teams."