Major Collision Investigation Unit detectives are investigating the circumstances surrounding a fatal crash in Lancefield this afternoon.
It's believed a white four-wheel drive travelling north along Pyalong Road left the roadway and struck a tree just before 2.30pm.
A yet-to-be formally identified passenger died at the scene.
A second passenger was airlifted to hospital with life-threatening injuries.
The driver of the vehicle was taken to hospital with minor injuries.
The exact circumstances surrounding the crash are yet to be determined and investigations remain ongoing.
Anyone who witnessed the vehicle prior to the collision, with dashcam footage or information is urged to contact Crime Stoppers on 1800 333 000 or www.crimestoppersvic.com.au.