Acting Sergeant Brendon Medley, of Portland Highway Patrol, said the accident happened about 4.30pm on Hansen Road just after the speed zone changes to 100km/h.

He said the occupants of the first car were sightseeing in the area and had slowed when the second car came over the crest and ran into the back of it.

“It was a heavy impact,” Acting Sergeant Medley said.

An Ambulance Victoria spokesperson Bianca Villarosa said seven people were assessed by ambulance officers.

A woman in her late teens was flown to The Alfred hospital in Melbourne with leg and arm injuries and another woman, also in her late teens, was flown to the Royal Melbourne Hospital with head and chest injuries.

Four others were taken to Hamilton Hospital including a man aged in his 50s with back injuries and a woman, also believed to be in her 50s, with rib injuries. A man in his 20s received arm and shoulder injuries and a teenage girl was taken to hospital with a head injury.

Another woman aged in her 50s was assessed at the scene but not taken to hospital.

Acting Sergeant Medley said most of the people involved in the accident were from the local area, except two  of the three occupants in the first car who were from Melbourne.

He said investigations were continuing.