Red Bull Racing chief technical officer Adrian Newey says the squad is likely to lose more ground to Mercedes and Ferrari this season and that the best-case scenario will be to maintain the gap.

Despite looking to switch power unit suppliers for 2016, Red Bull failed to secure a new deal and will now remain with Renault power, albeit rebranded as TAG-Heuer.

"Our hope for 2016 is to just maintain that gap but with Ferrari and Mercedes expected to step up, towards the end of the year we might be further behind than we were last year," Newey confirmed in an interview with The Hindu.

He also reiterated again that dominance of the Mercedes and Ferrari power units is not healthy for the sport.

"It is important to find the right balance between the chassis, engine and the driver for the sport to be competitive, but right now the engine is dominating, which is unhealthy," Newey stressed.

"Cosworth came with a winning engine in 1967 that was exclusively for use by the Lotus team. It became very clear that the engine was going to be dominant. Then, Lotus agreed to waive its exclusivity to allow others to use it for the good of the sport. Unfortunately, that sort of attitude doesn't seem to exist any more. If the sport is not healthy, what's the point in winning?"

Meanwhile, he said that Mercedes' dominance now is different to that which Red Bull enjoyed from 2010-2013.

"Though we managed to win four [successive] titles, in 2010 and 2012 the battle went down till the last race," Newey pointed out. "Secondly with aero and chassis it is out on view, people can see designs, understand and copy. But with the engine formula you can't see your competitor's engine. The only way to catch up is with huge investments and people moving. Ferrari improved from 2014 to 2015 but it cost a lot and needed people from Mercedes."