Detectives from the Major Collision Investigation Unit are appealing for witnesses following a car crash in Wonthaggi yesterday afternoon.
It is believed a car veered off Merrin Crescent and struck a tree at 3:50pm.
The driver of the car who was arrested at the scene, a 41-year-old Morwell man, has been released pending further investigation.
The front seat passenger, an 11-year-old boy, received life-threatening injuries and remains in hospital.
Other occupants, a 3-year-old girl and a 17-year-old girl, received serious injuries and non-life-threatening injuries respectively and were taken to hospital.
The circumstances surrounding the crash are yet to be determined and the investigation is ongoing.
Detectives are appealing to anyone who saw a black hatchback travelling in the Wonthaggi area, particularly Merrin Crescent, in the lead up to the crash to come forward.
Anyone who witnessed the crash or with dash cam footage leading up to the crash is urged to contact Crime stoppers on 1800 333 000 or submit a confidential crime report at www.crimestoppersvic.com.au.