The family of Iraena Asher say they will sue the police over the bungled handling of her call for help and have accused senior management of blocking their requests for information.

Ms Asher's distraught parents, Betty and Mike, last night broke their silence on their daughter's disappearance, saying they were at the end of their tether after feeling let down by the police.

Ms Asher disappeared at Piha, west of Auckland, last October after ringing 111 to ask for police help.

The 25-year-old said she was in danger and being pressured for sex but police sent a taxi, instead of a patrol car, which went to a street in Onehunga. She has not been seen since.

Mr and Mrs Asher are adamant that if their daughter's call for help had been treated properly at the communications centre the student and part-time model would be alive today.

They say Iraena died "a martyr" to improve the communications system which is still putting the public at risk.

It is partly for this reason, and partly for Iraena's memory, that they are proceeding with civil action against the police.

" ... We know that is like hitting your head up against a brick wall, but you have to make a stand and do the right thing," said Mrs Asher.

"We have to do that for our daughter."

Mrs Asher said they decided to take action earlier this year but the police had been stalling over the family's request, through their lawyer, for information about Iraena's case.

"They are doing stall tactics because that's the way they operate. They have no respect for us."

Mrs Asher said she and her husband were private people and had stayed silent about their dealings with the police until now "out of dignity and respect".

"But there comes a point where you try to do the right thing and all you come up against is a brick wall."

Mrs Asher said the family had been put in a position of having to spend a lot of money on lawyers to obtain the police information before advancing the lawsuit.

Breaking into tears, she said: "Our daughter was an amazing, beautiful daughter and ... I want to believe she hasn't died in vain. I don't see why now we should have to struggle and struggle and be victimised over and over again.

"The police should be doing the right thing for us."

A spokesman for the Office of the Commissioner was not aware of the Asher family's plans to take a civil case but said police would not make any comment until after the action.

The spokesman said there might be reasons for some material not being provided to the family yet, such as ongoing disciplinary action or inquiries.

The police did abide by the official information process and the family could complain to the Ombudsman.

Mr and Mrs Asher said the impact on their lives and those of their three other daughters had been huge since October.

Not a day went by when the couple did not think about their daughter and how police handled her call for help.

"It's devastating," said Mrs Asher. "It's such a horrible thing to think about what she was going through in the hours before she disappeared."

The couple have both been diagnosed with depression and post-traumatic stress, factors which have limited their ability to work until recently.

Two of their other daughters have moved away from Auckland, the memories of their sister making it too painful for them to stay.

Mrs Asher said the family felt continually revictimised by the police and their handling of their daughter's case.

The latest insult came this week when they returned home to find half a dozen messages from the media about the review of the communications centre being released.

Mrs Asher was pleased the review was carried out independently and the panel had produced such a scathing report.

"You can't bury something like that. I didn't think they were taking it seriously enough. [Rob Robinson] didn't look to me as if he was taking it seriously enough."