Luca di Montezemolo has warned he is prepared to take action to improve Formula One.

Fiercely critical of the sport's direction, culminating in the new era of quiet, hybrid engines, the Ferrari president recently wrote a letter inviting the sport's major stakeholders to an emergency meeting.

Speaking with the German newsmagazine Focus, the 66-year-old laid out his repeated fears: "The rules are too complicated, the drivers have turned into taxi drivers.

"They must save fuel and tyres instead of being fast. The teams have to decide how much fuel they're using and how many tyres are wearing out.

"Before, it was the best man winning in the best car.

"Now, the viewers - the ones in the stands and the ones in front of their TVs - no longer understand. As it is now, we must do something. Otherwise Formula One has no chance," he said.

Montezemolo said it is up to F1 chief executive Bernie Ecclestone to act, and "If he doesn't, I'll do it myself. I see it as my duty," he insisted.

"The need to do something to recover the lost charm of Formula One is urgent," said Montezemolo.

At the very same time, there are those who believe Ferrari has more pressing issues to address, such as the pace of its F1 car.

It is believed engine chief Luca Marmorini has now paid the price of Ferrari's 2014 struggle by leaving Maranello, and the latest rumours are that designer Nikolas Tombazis and technical chief Pat Fry are also in doubt.

The trend has Ferrari insider Leo Turrini worried.

"I do not think the decline in performance can be attributed to individuals," he said in his Quotidiano blog, instead pointing out a culture change since the end of the ultra-successful Michael Schumacher and Jean Todt-led era.