An 18-year-old Cranbourne woman and a 16-year-old Frankston boy riding in the allegedly stolen car died at the scene. An 18-year-old Baxter man was treated for minor injuries.
The occupants of the other vehicle – a 39-year-old woman and two girls aged six and nine, all from Lynbrook – are being treated for non-life threatening injuries.
The exact circumstances are yet to be determined.
A witness told Nine News it appeared as though the driver of the allegedly stolen car lost control of the vehicle.
“The blue car was going fast down this way and lost control … hit the other car from the other side and some of the guys tried to run away.”
Much of the South Gippsland Highway remains closed between Camms Road and Duff Street on Monday morning.
One citybound lane opened about 7am, and all southbound lanes remain closed.
VicRoads said delays would continue and motorists should consider using Narre Warren Road or the Western Port Highway.
The incident brings the road toll to 181 lives lost, 61 more than the same time last year.