Mary Quy was 69 when she vanished from her home at 29 Cobra Street in the early hours of February 11, 1991.

There was no sign of a struggle or disturbance. The woman described as "a lovely lady" did not take her shoes, reading glasses or purse.

Extensive police searches found no trace of Ms Quy and examination of her bank records showed no activity over the years.

In 2005 State Coroner Paul MacMahon said although a body had not been found "it was fair to assume she had died". He found the manner and cause of her death was unknown.

Ms Quy is still listed as a missing person.

The sad case sticks in the mind of Detective Senior Constable Sue-Ellen Scott who reinvestigated the disappearance prior to the coronial inquest.

"It was a very strange situation and it is terrible that we still do not know what happened," Detective Scott told the Daily Liberal.

"Ms Quy was living with her children and grandchildren. She was last seen by her daughter at 1am. She was reported missing at 5am.

"Her home was in the process of being sold and contracts had been exchanged for the purchase of a new property."

The house, opposite McDonald's family restaurant, was later demolished to make way for a motel.

Detective Scott said Ms Quy was not in the habit of wandering off and she did not suffer from any significant medical or mental conditions.

Diagnosed with high blood pressure and a heart condition, she had experienced a bout of influenza in the days leading up to her disappearance but was reported to have been in "good spirits".

"It is impossible to say if she left of her own accord or was taken by force," Detective Scott said.

Ms Quy was a widow who had lived in Dubbo for a long time. She went to church every Sunday and attended a rosary group during the week. She was secretary of the Catholic Women's League.

"Ms Quy was a harmless woman who was not a threat to anybody," Detective Scott said.

"Investigations found she was not mixed up in anything unusual. She lived a very ordinary life. That is what makes her disappearance so disturbing.

"It was totally out of character for her leave the house without any of her possessions."

Detective Scott said police records indicate Ms Quy was wearing a white sleeveless dress patterned with multi-coloured polka dots.

She was 154 cm tall, of medium build with a fair complexion, fair collar-length hair and brown eyes.

She was believed to have been carrying a pale pink pillow.

Eight witnesses gave evidence during an inquest held in Dubbo on July 18 and 19, 2005.

The court was told about an anonymous call made to police in June 1999 claiming Ms Quy had been murdered "as part of a contracted professional hit".

Four days later another call, believed to have been made by the same person, claimed another member of the Quy family would also be killed.

The court was told the calls had been traced to a phone booth in Queanbeyan.

A police investigation found the claims were not considered to be genuine or credible due to the "mental status" of the person alleged to have made the calls.

Coroner MacMahon dismissed suggestions of a contract killing due to lack of evidence and credibility. He said the claims did not warrant further attention.

Detective Scott said police were still actively investigating the disappearance of Ms Quy.

"Her file shows that police did a very thorough job carrying out searches in a number of areas in and around Dubbo," she said.

"Divers spent a considerable amount of time searching the Macquarie River.

"Notes in the file describe how appreciative police were of assistance provided by local media outlets at the time.

"There was special mention of the Daily Liberal for running stories about the disappearance to keep interest going in appeals for information.

"Although 25 years have passed police are still seeking assistance from the public. We hope that Ms Quy's body will one day be found and that there will be an explanation about what happened to her."

People with information should call Crime Stoppers 1800 333 000 or Dubbo police 6883 1599.