The reigning world champion was seen sitting at the end of the pit lane for a long time while the green light was displayed.

Grand Prix Foundations: Street Tracks in F1

Cars, including the Mercedes duo of George Russell and Lewis Hamilton, were stacked up behind Verstappen's Red Bull as he waited to pull away. 

"Unless he had an issue there, I think it will be quite difficult to argue against that he was making himself a gap and impeding the others. But maybe he had a gremlin he was sorting out," Sky F1's Martin Brundle said. 

Sky's pitlane reporter Ted Kravitz added: "If they do give him a penalty, which I don't think they will, they'd have to give everyone else a penalty as I've watched plenty of people do that. 

"Maybe it was in a more exaggerated way but when you can't go out on the track and stand in anyone's way when you're trying to get a gap, the only way you can do that really is in the pit lane.

"So I think that's fairly standard stuff but we'll see what the stewards do."

Verstappen is also being investigated for potentially impeding AlphaTauri's Yuki Tsunoda in Q2. 

Several drivers including Verstappen are facing investigations over possible impeding incidents in the final few corners amid a hectic end to Q1. 

Separately, Logan Sargeant is under investigation for blocking Stroll.