Nineteen people have been injured, some critically, after a car was deliberately driven into pedestrians outside a major train station in Australia.

The crash outside Flinders Street station in Melbourne's central business district (CBD) happened at about 4.45pm local time on Thursday.

The driver and a second man have been arrested, police said. Officers called it a “deliberate act” but said there was no evidence to suggest terrorism as a motive.

Police said the 32-year-old driver was an Australian of Afghan descent who had a history of drug use and mental health problems. The second man, 24, was arrested nearby and found to be carrying a bag of knives while filming the crash, officers said.

Australian media reported that a preschool-aged child was among the injured.

Images showed a white Suzuki SUV that appeared to have collided with a tram shelter. Its front was significantly damaged, however, with the bumper crushed back behind the line of the wheels.

Police and emergency services attend the scene of the crash on Flinders Street (Reuters)

Victoria Police said: “Police and emergency services remain on the scene and will do for the foreseeable future. The crime scene is active and will remain in place for some time.

“We urge people who can avoid the area, to avoid the area. People may have items or vehicles within the crime scene area, however they will not be able to access these until the area is reopened.

“Victoria Police will also continue to provide a strong police presence in the Melbourne CBD tonight.”

The white car surrounded by investigators (ABC)

A witness told ABC: “I was crossing Flinders Street on the way to the train station. I heard an engine rev behind me and I heard a thump.

“I turned around and saw the white SUV streaming through the intersection and just seeing people literally getting thrown into the air as it hit them. Then it went through the intersection within a second or two and then went ploughing straight into the tram stop where it came to a dead halt.”

Melbourne car crash Show all 12 1 /12 Melbourne car crash Melbourne car crash Police and emergency personnel work at the scene of where a car ran over pedestrians in Flinders Street in Melbourne REUTERS Melbourne car crash The white car surrounded by investigators ABC Melbourne car crash A police officer detains a suspected man Twitter/LACHLANVE via Reuters Melbourne car crash People have been injured, some seriously after the crash PA Melbourne car crash Victoria Police Commander Russell Barrett speaks to the media on Flinders Street AAP/Joe Castro via Reuters Melbourne car crash Police and emergency services attend to the scene Reuters Melbourne car crash The white SUV sits in the middle of the road AFP/Getty Melbourne car crash Members of the public stand behind police tape after the driver of a vehicle that ploughed into pedestrians at a crowded intersection was arrested Reuters Melbourne car crash Police and emergency personnel work at the scene AFP/Getty Images Melbourne car crash Police and emergency services attend the scene of the crash on Flinders Street Reuters Melbourne car crash The scene where a car ran over pedestrians AFP/Getty Melbourne car crash Police and emergency personnel examine the scene of where a car ran over pedestrians AFP/Getty

“We believe based on what we have seen that it is a deliberate act,” Victoria Police commander Russell Barrett told media in Melbourne. “The motivations are unknown.”

Flinders Street is a major road that runs alongside the Yarra river. The crash happened in the first week of school summer holidays.

Another witness, Lachlan Read, told the Herald Sun the whole attack lasted about 15 seconds. “It was bang, bang, bang. It was just one after the other.

“The last bang the car stopped,” the 20-year-old said. “There were bodies on the ground and people running up to them – it was mayhem.”

In January, four people were killed and more than 20 injured when a man deliberately drove into pedestrians at a spot just a few hundred metres away from today’s incident. Police said the earlier attack was not terrorism-related.