Prahran Highway Patrol officers are investigating a hit-run collision in Malvern East earlier this week.
It is understood a black BMW sedan collided with a white Kia SUV on the Monash Freeway about 6.10pm on Monday, 7 June.
The driver of the Kia, a 35-year-old Seaford man, was given medical treatment at the scene.
His front passenger, a 31-year-old Somerville woman, was taken to hospital with serious injuries.
Three children, aged 4 months old, 8-years-old, and 6-years-old, were all taken to hospital with non-life-threatening injuries.
Officers have been told that prior to the collision, the BMW was seen driving erratically and at speed between High Street and Warragul Road.
The driver of the BMW fled the scene of the collision, losing a wheel in the process.
Officers later located the unoccupied vehicle at a carpark on Warragul Road.
Investigators are keen to speak to anyone who might have witnessed the collision, or anyone with dash cam footage in the vicinity of the Burney Tunnel, High Street and Warragul Road between 5.50pm and 6.30pm.
Anyone with information that could assist investigators is urged to contact Crime Stoppers on 1800 333 000 or www.crimestoppersvic.com.au.
