A man is fighting for his life after his vehicle was struck by a car that police believe may have sped through a red light at a major intersection in Melbourne's south-east.
The man was driving north on Springvale Road shortly before 5:00am when he was hit by a car travelling east along the Princes Highway, police said.
Witnesses have told police the eastbound car was speeding and ran a red light at the time of the crash.
Police said they were trying to determine if it had been stolen.
The car was carrying six people, including a woman in her 20s who Ambulance Victoria said suffered life-threatening injuries to her head, chest and legs.
It is believed she is now in a stable condition.
The driver and sole occupant of the northbound vehicle, a Parkdale man in his 40s, was taken to the Alfred Hospital in a stable condition, but is now listed as being in a critical state.
Superintendent John Fitzpatrick said the "heavy impact" of the collision meant the northbound car was pushed a significant distance across the intersection.
Springvale Road was closed in both directions and the Princes Highway outbound for much of the morning as police carried out investigations.
"If you have a look at the scene and where the debris has been strewn across, there's a fair bit of investigation that needs to take place to reconstruct it," Superintendent Fitzpatrick said.
The five other occupants of the eastbound car, aged in their mid-teens and early 20s, were taken to hospital in a stable condition with head, leg and back injuries.
Superintendent Fitzpatrick said some people in the car were not wearing seat belts.
"Anytime that you've got a sedan that's got the capacity to hold five people safely carrying six people is irresponsible," he said.
"You shouldn't really do it."
