A five-car smash on a freeway outside Melbourne has left a child with severe facial injuries and a teen with an injured spine, as well as causing long tailbacks for motorists at the end of the long weekend.
Up to five cars and a horse float were involved in the smash on the Hume Freeway in Kalkallo on Monday afternoon, an ambulance spokeswoman said.
A nine-year-old boy was airlifted to The Royal Children's Hospital with severe facial injuries while a teenage girl has possible spinal injuries.
It was previously thought by Ambulance Victoria that the injured child was a girl but the hospital has since confirmed it was a boy.
A hospital spokeswoman told AAP they are both in a stable condition.
A woman in her 30s with a neck injury was taken to The Royal Melbourne Hospital and a fourth person was assessed at the scene.
Police say the car towing the horse float rear-ended another car and set off a chain reaction.
The three horses in the float escaped uninjured.
The Hume Freeway was closed inbound at Kalkallo following the accident with traffic banked up in a queue stretching about 35km.
It has since reopened but traffic early in the evening remains heavy for those returning to the city at the end of the Queen's Birthday holiday.