A driver has been arrested after his truck ploughed into a traffic light in central Melbourne, leaving five pedestrians injured including two critically.

The truck driver did not stop to help the injured after the crash near the intersection of City Road and Power Street at Southbank on Thursday night.

While performing a left-hand turn, the B-double tanker is believed to have cut the corner and mounted the footpath before taking out the traffic light which fell to the ground.

Five people on the street, four men and a woman all believed to be aged in their 20s to 30s, suffered lower body injuries in the crash and were taken to hospital.

Two of the men are critically injured, while the three other pedestrians are in a serious but stable condition.

A motorist who saw the crash unfold followed the truck as it continued to travel along Power Street.

The information they relayed helped police track down the truck at Truganina in the city’s outer west and arrest the driver.

The 64-year-old man from Wyndham Vale is being interviewed by police, with charges yet to be laid.

Major crash detectives are expected to remain at the cordoned-off scene overnight.

-AAP