Key Points:

The survivor of the brutal Auckland RSA triple murder in 2001 says she deserves her day in court.

Susan Couch today asked the Supreme Court in Wellington for the right to go to trial and sue the Department of Corrections for damages.

Ms Couch suffered serious injuries in the attack and spent years in rehabilitation after William Bell wounded her and killed three other employees at the Mt Wellington-Panmure RSA in December 2001.

It was "very stressful" coming to court today, but it was something she had to do, Ms Couch said outside the court.

"I hope to get my day in court.

"I think I'm entitled and deserve my day in court."

Ms Couch, who now walks with the aid of a cane, said she maintained her fitness despite her physical injuries by regularly exercising but the emotional scars were "a work in progress."

She wanted to see someone held accountable for what happened.

"I would like the Department of Corrections to get a wake up call... and make some changes."

The Court of Appeal ruled against Ms Couch last year in her bid to sue the Department of Corrections for $2.55 million, but the Supreme Court later granted her leave to appeal on the grounds of possible negligence.

Bell had 102 previous convictions and was on parole when he went to the RSA where he had worked as a barman. He killed Mary Hobson, Wayne Johnson and William Absolum.

Ms Couch's lawyer, Brian Henry, told the court today he should be allowed to argue in a trial that Bell's probation officer had a duty of care to protect the public.

The probation officer, who has name suppression, should have never permitted Bell to work at the RSA, or at least warned the staff of his previous convictions.

"It's putting a wolf in sheep's clothing amongst the sheep who are the workers," Mr Henry said.

He said the probation officer completely failed to do her job .

For the Department of Corrections, John Pike said the department had admitted there were system failures in Bell's case.

The probation officer was over-worked and inexperienced, and put in charge of a man who turned out to be a "cunning, malicious, psychopath".

However, in Bell's long history of offending there was only one serious violent conviction, which was the aggravated robbery on which he had been paroled.

The probation officer and department would not have been able to foresee Bell would commit such a terrible crime and therefore the duty of care was not a factor, Mr Pike said.

"There was nothing special about Bell, there was nothing special about an overworked probation officer."

Probation officers were not required to warn the community at large about offenders and were only required to endeavour to warn "special groups" when the certain risk factors were identified .

Chief Justice Elias, Justice Blanchard, Justice Tipping, Justice McGrath and Justice Anderson reserved their decision.