Several people have been injured following a serious incident outside Flinders Street Station on Thursday afternoon.

3AW reports a four-wheel drive hit pedestrians as it drove through the intersection at Flinders Street and Elizabeth Street. Heavily armed police have surrounded the area and the driver has been arrested.

At least 16 people may have been injured, according to the Herald Sun. Ambulance Victoria says its paramedics are treating 12 people at the scene. Three people have been taken to the Alfred Hospital; three have been taken to the Royal Melbourne Hospital; a pre-school aged child with a head injury has been taken to Royal Childrens Hospital in a serious condition.

Flinders Street remains closed between Swanston Street and Queen Street.

Police are advising pedestrians and vehicles to avoid the area. Metro Trains is advising passengers "to defer travel through Flinders Street Station" and to "interchange for services at Southern Cross and City Loop Stations."

Any witnesses are advised to report to the Melbourne West Police Station at 313 Spencer Street. Victoria Police has also asked members of the public who have video or images that might assist police with their investigation to upload them here.

For updates follow Victoria Police, 3AW and PTV.