Red Bull protest Mercedes' DAS system at F1 opener

The action concerned the cars of six-times world champion Lewis Hamilton and team mate Valtteri Bottas, with team representatives summoned to stewards at the Red Bull Ring.

Mercedes, who dominated practice with Hamilton fastest in both sessions, were running the system for the first time at a race weekend after it raised questions in pre-season testing.

The governing FIA has said already that DAS will not be allowed next year, despite the cars remaining the same due to new rules being postponed to 2022, but has not banned it for 2020.

"I think the fundamental question for us is 'does it comply with the regulations in what is a fundamentally grey area?'" Red Bull team boss Christian Horner told reporters.

"We do want clarity on it because it does have an impact regarding the rest of this year. It's something that's been outlawed for next year but the question is 'Is it right for this year?"

DAS allows a driver to change the 'toe angle' of the front wheels by pushing and pulling on the steering wheel, rather than just moving it sideways.

Mercedes team boss Toto Wolff said a clarification would be welcome.

"We think we are on the right side. There was a lot of talking and exchange with the FIA, that is the reason why we have it on the car. So we will both bring our arguments forward and then, let's see," he added.

"We are aware that we don't want to end up with a big debate on Sunday night. I think Red Bull, I think Christian is going to take the right actions.

"You know, controversy and different judgement on engineering innovation has always been part of Formula One. This is what's to be expected in a way. It's part of the racing."

Formula One has a long-established process for challenging innovations that exploit loopholes in the rules, with teams making a protest and presenting their arguments.

The stewards then make a ruling, which can in turn be appealed.