This week marks 18 years since the store manager got into a small red vehicle in Keppel Street in the early hours of December 7, after a night out with friends.

She has never been seen since.

In March police announced a $1 million reward for information that leads to the arrest and conviction of the person or people responsible for Ms Vaughan's death.

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Homicide police also revealed in the course of the initial investigation, detectives seized a smell red vehicle, from which very weak DNA samples had been recovered.

Those DNA samples are still being forensically re-examined, however, due to the complex nature of the testing, Homicide Squad Commander, Detective Superintendent Scott Cook said it is expected the results will take some time to obtain.

Nine months on, Supt Cook said the investigation remains ongoing, with detectives continuing to follow up leads on persons of interest in the matter.

Detective Superintendent Scott Cook said on Thursday police still believe there are people in Bathurst who have information relating to Janine's presumed murder, but have yet to come forward.

"Investigators from the Unsolved Homicide Squad's Strike Force Toko II are continuing to conduct inquiries, as they acknowledge the recent 18th anniversary of the disappearance and suspected murder of Janine Vaughan.

"The investigation remains open, and a team of investigators is continuing to explore lines of inquiry and persons of interest in an effort to find out what happened to Janine," he said.

Supt Cook made no further comment on the status of the DNA.

Back in March he said forensic experts are now able to delve deeper into partial DNA, familiar DNA and blood lines and investigators are hopeful that what they find in the vehicle, belongs to Janine.

He said police know who the owner of the car was and will be talking to him again.

He reminded the community a $1 million reward for information which leads to the arrest and conviction of Janine's killer remains in place, and said police believe a local living in Bathurst at the time was involved.

"Information suggests someone in the community knows something and police are still appealing for anyone with information to come forward."

Anyone with information is urged to call Crime Stoppers on 1800 333 000.