Warrnambool police highway patrol commander Sergeant Lisa McRae said the highway remained closed near Dura Lane for hours as major collision investigators assessed the scene.

She said traffic diversions were in place until about 11am Thursday.

Sergeant McRae said both the station wagon and B-Double truck were significantly damaged.

She said local highway patrol and specialist units from Melbourne worked together at the scene as the major collision unit conducted their investigations.

She urged anyone with information or dash cam footage of the fatal crash to contact Crime Stoppers.

Thursday, 8.20am:

Victoria Police major collision investigators are still on the scene of a fatal crash west of Port Fairy.

A 38-year-old Portland woman died just before 6pm on Wednesday.

The collision happened west of Port Fairy on the Princes Highway, through the S bend and about 200 metres east of Dura Lane.

A spokesman described the collision involving a station wagon driven by the woman and an empty B-double livestock carrier as a "partial head-on".

The scene was left intact overnight as MCIU detectives conducted inquiries.

It's believed the B-double was heading west on the Princes Highway.

The exact circumstances of the crash are still the subject of inquiries.

The truck driver was not injured.

A spokesman said SES crews were sent home on Wednesday night while police took over at the scene.

"We are still on-site," the spokesman said.

"The MCIU members have been here all night doing their investigations. They are still trying to stitch together what's exactly happened."

Heavy haulage has just arrived at the accident scene, the highway is still closed and expected to be closed until at least 10am.

Police, SES, local Country Fire Authority units and ambulance officers all attended at the collision scene.

Wednesday night: A woman has died after a collision with a truck at Port Fairy this afternoon.

The woman, who is yet to be identified, was the sole occupant of the car which was involved in the collision with an empty livestock truck on the Princes Highway just before 6pm. She died at the scene.

The driver of the truck was uninjured and is assisting police.

Major Collision Investigation Unit detectives are investigating the circumstances surrounding the fatal collision.

Anyone who witnessed the collision or anyone with dashcam footage is asked to contact Crime Stoppers on 1800 333 000 or visit www.crimestoppersvic.com.au

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