Police reopen case of Melbourne woman who vanished after stopping on highway

Police have reopened the investigation into the 28-year-old disappearance of a Melbourne woman who was last spotted on the side of a highway.

Marcia Ryan, 33, vanished late on August 19, 1996 after she stopped her Mitsubishi Sigma (registration DUP002) on the side of the Princes Freeway, near Moe, in Victoria's Gippsland region.

She had her dog, Ziggy, a black-and-white heeler/border-collie cross, with her at the time.

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Ryan was travelling to visit her parents in Queensland.

Her car was later found abandoned on the highway near Moe and her wallet was discovered on the roadside at Darnum, about 23km away.

A truck driver spotted her in a distressed state but she declined the offer of a lift and continued walking on the highway.

Ryan was described as 160cm tall, with brown hair and brown eyes and of medium build.

During the past 28 years, there have been numerous reported sightings of Ryan that night.

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The case was also the subject of an ABC radio series that claimed to have found new evidence.

Victoria Police say detectives are now "actively investigating" her disappearance and any new information received about the case will be thoroughly assessed.

Anyone with information should call Crime Stoppers on 1800 333 000.