7 News reports that horrified witnesses have described bodies "flying everywhere".
Paramedics are assessing 12 people at the scene located in Melbourne's CBD, with taken to hospital.
A pre-school aged child has been taken to the Royal Children's Hospital in a serious condition.
Another pedestrian has been taken to the Alfred Hospital. The extent of their injuries it not known.
A witness told 3AW that the car failed to stop at the intersection, instead 'mowing' pedestrian down.
"As it (the car) approached this intersection ... it just mowed everybody down, people were flying everywhere," witness Sue said.
Police are appealing for any witnesses to come forward.
This is a developing story.