Mercedes sparked intrigue during Formula 1's pre-season testing running after debuting the innovative steering device that allowed drivers Lewis Hamilton and Valtteri Bottas to adjust the toe angle of the car from the cockpit.
Red Bull was known to be planning a protest against Mercedes in Australia had the team used DAS, only for the race to be cancelled ahead of opening practice.
Red Bull F1 team principal Christian Horner told Motorsport.com there would be "question marks" remaining over Mercedes' DAS system heading to the revised season ºopener in Austria.
Mercedes confirmed during first practice for the Austrian Grand Prix on Friday that it was testing DAS on its cars ahead of a possible use in the race, with Bottas and Hamilton shown to be adjusting their steering wheel through the session.
Speaking on Sky Sports F1 during FP1 at the Red Bull Ring, Horner revealed he would seek clarification from the FIA over the use of DAS.
"We'll wait to see if it is fitted to their cars," Horner said. "Obviously it's a complicated system, it's a clever system.
"We're after some clarifications from the FIA, and start raising some questions about it."
DAS is permitted under the 2020 technical regulations, but has already been outlawed for next season, even with the carry-over of the current cars.
But question marks are expected to remain over how DAS complies with F1's parc ferme regulations that limits what teams are allowed to change with the set-up of their cars following the start of qualifying.
Teams may look to lodge a protest on the grounds that adjusting the toe angle of the front wheels through the movement of the steering wheel does not fully comply with this rule.
FIA race director Michael Masi said in pre-season testing that queries from teams would be dealt with on a "one-to-one basis", and would not be drawn on whether DAS would be in breach of the sporting regulations.