Major Collision Investigation Unit are investigating following a fatal collision in Mount Moriac this morning.
It is understood a Mazda CX5 and a Toyota Landcruiser collided near the intersection of Cape Otway Road and the Princes Highway about 11.30am.
A male passenger of the Mazda, who is yet to be formally identified, died at the scene.
A female passenger of the Mazda was airlifted to hospital with serious injuries.
The driver and the fourth passenger of the Mazda and the sole occupant of the Toyota were taken to hospital with non-life-threatening injuries.
The female driver of the Mazda is under police guard.
The exact circumstances surrounding the collision are yet to be established and the investigation remains ongoing.
It is expected the road will be closed for some time while MCIU detectives process the scene.
Anyone who witnessed the collision or with dashcam footage is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au
