Beth Cassilles made her impassioned appeal direct to Mr Barr on Friday by ringing Chief Minister's Talkback on ABC Radio Canberra.

She was frustrated by the lack of progress in the case of her daughter Laura Haworth, who was last seen on January 5, 2008 leaving a friend's house in Queanbeyan. Laura was then aged 23 and had two children of her own, then aged three and four.

The young woman has not been seen or heard from in the last decade. The last 10 years have been torture for her family.

"I've had some very dark times in my thought processes. It's a constant in my life," Ms Cassilles told The Canberra Times.

"The worst part is thinking she's in trouble somewhere and needs help."

Ms Cassilles said she used talkback radio to contact Mr Barr direct out of sheer frustration. Mr Barr said he would contact ACT Policing on her behalf.

"I don't know who else to turn to," she said, afterwards.

"It takes a lot of courage and effort on my part to pick it up each time and it is incredibly draining emotionally and I was just hoping to get some support from someone else, in working with the police."

Ms Cassilles said it was difficult for historical missing person cases to compete against more urgent crimes such as murder when the same finite policing resources were assigned to investigate both.

She had no issue with individual police officers who were well-meaning but instead with the level of resourcing available to long-term missing persons cases.

"The case is never closed," she said.

"They were quite active in the first few years and in more recent years they have been saying they don't have the resources to put to it because any time there's a homicide in Canberra, they need to put their resources into that instead of a missing person.

"So the cycle I'm on with them is, I don't hear from them for a long time. I ring up and find out who the case officer of the day is. They don't know much about the case, they get themselves across the case and come and visit me and say, 'We're going to do this, that and the other. We're reviewing the whole thing and we'll finish the review in three months and get back in touch'. And then they don't get back in touch.

"Then I'll ring them up again and I'll be given a new officer who will say the same thing, 'We're going to do a review'."

ACT Policing was asked to comment on those claims. A spokesperson said police were investigating eight long-term missing people.

"The ACT Policing investigation into the disappearance of Laura Haworth remains open and urge the community to crime stoppers on 1800 33 00 if they have any information regarding Laura," a statement read.

Ms Cassilles said she did not understand why a coronial inquest had not been held into her daughter's disappearance.

"Usually a long-term missing person's case would go before the coroner well before this," she said.

"That can often trigger more information and give the police more power to do something. It's not something I particularly want to go through but I think it could help."

ACT Attorney-General Gordon Ramsay said there was no time period that would trigger an inquest into a missing person's case.

"I understand and sympathise with the family and their desire for answers. This is an open investigation, and for that reason the government cannot comment further at this time," he said.

"The coroner has jurisdiction to hold an inquest into a suspected death under the Coroners Act 1997, but there is no specific number of years or particular circumstance in relation to missing people that means an inquest must be held.

"Each case is assessed on its own merits and where there is a suspected death, an inquest may be held."

Ms Cassilles said her daughter was leaving a house in Queanbeyan where she had been staying when she disappeared. The last person to see her was a male friend. Her children, who are now 13 and 14, had not been living with her, but instead with relatives.

Her red Mazda 121 was found two weeks later on January 19, 2008 at the Kanangra Court car park in Reid. There was no sign of her. Her phone and handbag were missing.

Ms Cassilles said Laura had been diagnosed with bi-polar disorder just before she disappeared but her family felt nothing was untoward.

"We didn't think anything was particularly wrong at the time," she said.

Summernats was on at the time, an avenue of investigation police had considered, her mother said.

"There was one theory a person from out of town had taken her," she said.

At the time of her disappearance, Laura was slim, 170cm tall, with blue eyes and her hair cut short and dyed red.

More information is available at missingpersons.gov.au