Bernie Ecclestone continues to voice concerns about the next generation of F1 engines, despite the manufacturers being well advanced with their design and build programmes.

The octogenarian has never been in favour of the change of specification, which comes complete with energy recovery systems and was pushed through by the FIA in an effort to make F1 'greener'. Although there are few complaints about the current breed of V8 units, teams are now facing serious cost hikes as manufacturers pass on the cost of developing the new turbocharged 1.6-litre V6s.

Having already railed against the cost and expected sound quality of the 2014 engines, Ecclestone turned his attention to the possibility of one or more manufacturer being left behind in the development race if initial design calculations prove to wide of the mark.

Speaking to Reuters from the Monaco Grand Prix, the sport's commercial ringmaster warned that more money would have to be thrown at the programme by anyone falling behind, with the potential for manufacturers to walk away if they cannot be competitive. Ferrari, Mercedes and Renault are all currently building a version of the new engine, with Honda having committed to joining the fray from 2015.

"The danger is, if one of those three gets it wrong, whoever they are, it's going to cost a fortune to catch up," Ecclestone noted, "And, as they are catching up, the others are going forward.

"At the moment, everything's fine, [but] there's very little anyone can do now. The danger is that all three think they've got the right engine. When reality sets in, it will be too late."

The prices being charged by the three existing engine providers vary wildly, with Renault being quoted as wanting as much as EUR23m a season. The French giant currently provides engines for four teams - Red Bull, Lotus, Williams and Caterham - and is expected to announce a deal with Toro Rosso at some point this weekend. Mercedes, which has already reduced the cost of its basic package, will continue to power its own team as well as McLaren and Force India in 2014, while Ferrari is expected to replace STR with Marussia and keep providing engines to Sauber, as well as its own works operation. The Italian package is reportedly the cheapest on offer, coming in at around EUR16m. Ecclestone is expected to meet with Renault chief executive Carlos Ghosn to discuss the issue of costs during the Monaco weekend.

"Some costs are costs, there's nothing you can do about it, but this is unnecessary cost because what we had was perfect," the Briton continued, "What's going on now, everybody's happy - happy with the F1 noise, happy with the costs, happy with everything.

"[The manufacturers] could produce [the current] engines and still make a profit at 25 per cent less than they are going to charge for these other engines."