The off-duty police sergeant who grabbed the driver alleged to have deliberately ploughed into pedestrians in Flinders Street in December, was called upon to restrain a dangerous passenger on a domestic flight two years earlier.

The sergeant was one of nearly 270 passengers on board a Qantas flight from Perth to Brisbane on October 17, 2015 when a drunken passenger confronted the plane's crew after a minor dispute.

Police drag a man from the scene of the Melbourne CBD Flinders Street crash in December. Credit:SEVEN NEWS

When the crew flight could not control the man, the sergeant identified himself as an off-duty Victoria police officer and offered to help. He got some other passengers to move and managed to drag the offender into the empty row of seats they'd vacated.

According to subsequent statements, the policeman had to restrain the offender alone while he continued to lash out because the plane had begun its descent into Brisbane and the crew were already buckled in.