KEY POINTS:

• A vehicle has struck pedestrians on Flinders Street in Melbourne
• The incident happened during rush hour, at approximately 4:45pm
• The driver of the vehicle and a second man have been arrested and are in police custody
• Police say 14 people are injured, several critical

Police say 14 people are injured, several in a critical condition, after a car ploughed into pedestrians in central Melbourne.

The car hit and injured a number of pedestrians outside Melbourne's Finders Street station, then crashed into a bollard.

Ambulance Victoria said paramedics were assessing people at the scene of the incident and police have held a media briefing.

Police currently believe the crash was deliberate but said it's too early to speculate on the motivations of the driver.

"At this stage we believe it is a deliberate act however we do not know the motivation and it is still early stages of the investigation.

The driver of the vehicle and a second man have been arrested.

The two men have not yet been charged, police said at the press conference.

Police and emergency services will stay at the scene for "a considerable period of time" and are urging people to avoid the area.

Footage taken by a witness shows a man in a white shirt and blue jeans being dragged from the passenger side of the vehicle.

Another witness photo shows a bearded man in a red and black chequered shirt sitting on the ground with his arms cuffed behind his back.

A preschool-aged child with head injuries is among the injured and has been transported to Royal Children's Hospital in a serious condition.

There are reports that 13 people have been taken to The Royal Melbounre and Alfred Hospital for treatment.

Witnesses described horrific scenes of "people are flying everywhere" as the carnage unfolded at the corner of Elizabeth Street and Flinders Street at 4.41pm this afternoon during peak hour.