Major Collision Investigation Unit detectives are investigating a fatal collision in Lysterfield last night.
Two vehicles collided head-on on Lysterfield Road, north of Wellington Road, about 11pm.
Despite the best efforts of emergency services to revive the female driver of one vehicle, she was declared deceased at the scene.
A male passenger from the second vehicle was airlifted to hospital with serious but non-life-threatening injuries.
The driver in the same vehicle sustained minor injuries and was taken to hospital under police guard.
The exact circumstances surrounding the collision are being investigated.
Anyone who witnessed the incident, with footage or any information is urged to contact Crime Stoppers on 1800 333 000 or submit a confidential report online at www.crimestoppersvic.com.au