Two women have died and a child has been flown to hospital after a head-on crash in south-west Victoria, police say.

Emergency services were called about 10:25am to a collision between a Jeep Cherokee and a Holden Trax in Mount Richmond, west of Warrnambool.

Victoria Police said the driver and front seat passenger in the Holden died at the scene, on the Portland-Nelson Road.

A child in the back seat, a girl, was flown to hospital with life-threatening injuries, police said.

The driver of the Jeep, a 50-year-old man, received non life-threatening injuries, they said.

Major Collision Investigation Unit detectives are investigating and anyone with more information is urged to call Crime Stoppers.