Two teenagers have been killed and three people seriously injured in a collision in Grangefields on Sunday.
Police have been told at least two off-road motorbikes and potentially a quad bike were being ridden on Beattys Road when the collision occurred about 6.35pm.
Five people were injured as a result of the collision, including an 18-year-old Altona Meadows woman who died at the scene.
A 43-year-old Altona Meadows man has been taken to hospital with non-life-threatening injuries.
A 17-year-old Hoppers Crossing boy was taken to hospital with life-threatening injuries, where he later died.
Two younger children, a six-year-old boy and 11-year-old boy, were taken to hospital with serious injuries.
The circumstances surrounding the collision are yet to be established.
Anyone with information is urged to contact Crime Stoppers on 1800 333 000 or at www.crimestoppersvic.com.au.