Red Bull Racing chief technical officer Adrian Newey says Mercedes and Ferrari are 'controlling' F1 as a result of regulations that he maintains are too heavily weighted towards engine performance.

One of the motorsport's most revered engineers having played a significant role in guiding Williams, McLaren and Red Bull Racing to ten world titles over the last 25 years, Newey has retained a fairly low profile of late following a decision to take a less front-line role within the Red Bull fold.

However, he has remained a vocal opponent of the current F1 era, which he feels places too much emphasis towards the V6 Hybrid power units introduced in 2014 on track and in turn has a rippling effect politically off track too.

Indeed, With Mercedes comfortably establishing itself as the class of the field since the new regulations were introduced and Ferrari making substantial gains in this area as a result, between them the manufacturers will supply eight of the 11 teams in 2016.

As a result, Newey believes their relative 'duopoly' means their customers will 'fear' contesting them on any issues, thus giving them majority power.

"Now the chassis regulations are tight but the engine regulations are very free. That's why teams like Mercedes and Ferrari, who build engines, have the advantage," he told the Times of India. "It's for these teams to supply engines to customer teams, and obviously they don't get the same software. Then it gets very difficult for the customer teams.

"Right now, we are in a situation where only Mercedes and Ferrari are in a position to win championship titles. That's the biggest problem in F1, where Mercedes and Ferrari are controlling the sport.

"The customer teams are always apprehensive going against Mercedes or Ferrari. I hope the FIA takes control of the situation. F 1 is at its healthiest when engine supplies are competitive for all teams."

After months of negotiations Red Bull will continue to run Renault engines in 2016, albeit under TAG Heuer branding, as well as the returning Renault team itself, while McLaren perseveres with its exclusive Honda deal.

Mercedes will continue to supply itself Williams and Force India, with Manor joining the stable, while Ferrari adds Haas and Toro Rosso to its long-term Sauber deal.