The man was interviewed by Major Collision Investigation Unit detectives and is assisting police with their enquiries.

He was released pending further investigation.

The 19-year-old Somerville woman died after a disagreement with her boyfriend.

Police said Nicole Beveridge and her boyfriend were walking along Frankston-Flinders Road in Somerville at 8.45pm when they had an argument.

The boyfriend walked away into nearby scrub, while Ms Beveridge went and stood on the road.

It is believed a delivery truck hit Ms Beveridge, who died at the scene.

Acting Senior Sergeant Madden said there were no skid marks found on the road and nothing to suggest high speed or hoon behaviour.

‘‘A female driver witnessed the accident and is assisting police,’’ he said. ‘‘Obviously the female witness is extremely traumatised.’’

Police were still trying to determine the exact details that led to the incident.

Miss Beveridge's visibly upset partner, who has paid tribute by placing a photograph of her and flowers at the accident scene, is assisting police with the investigation.

Information to Crime Stoppers, 1800333000 or visit their website here.