The head of the Sensible Sentencing Trust says a Supreme Court decision allowing a woman left for dead by triple murderer William Bell to seek damages from the Corrections Department won't open the floodgates to similar lawsuits.

Bell was on parole in 2001 when he carried out three killings at the Panmure-Mt Wellington RSA, and left Susan Couch seriously injured.

He was jailed for a minimum non-parole period of 33 years, later reduced to 30 years on appeal.

Ms Couch has sought leave to sue Corrections for $500,000 exemplary damages on the grounds that she may be owed a duty of care, arguing it had been negligent in the way it administered Bell's parole.

Today's Supreme Court decision allows Ms Couch to take her claim for damages to the High Court.

The Supreme Court said damages were available for negligence and damages arising out of personal injury should be covered, but it said there would be a very high test in order for the claim to succeed.

It said damages should not be available unless Corrections "consciously appreciated the risk the conduct in question posed to the safety of the plaintiff and proceeded deliberately and outrageously to run that risk causing harm to the plaintiff".

Sensible Sentencing Trust spokesman Garth McVicar said Ms Couch was "emotional" when he contacted her about the decision.

"When you've been battling for as long as Sue has been, you sort of prepare yourself for the worst I suppose," he told NZPA.

"She was overwhelmed and very grateful. It's only through the backing of many New Zealanders that we've got to where we currently are."

Mr McVicar said he didn't expect a plethora of similar complaints to follow, but he wasn't concerned if there was.

"I don't believe it will, the test is so high," he told NZPA.

"But even if it did open the floodgates, realistically the safety of the public should be of paramount concern. Whether the floodgates are opened or not, the system's got to change so the public's safe from these repeat violent offenders.

"I don't really care whether it opens the floodgates or we can't hold the Crown accountable in other cases. Ultimately we've got to change a system that's failing."

Mr McVicar said he was looking forward to seeing full disclosure from the Crown so the public could see all the failings in this case.

Ms Couch's lawyer Brian Henry said he would be seeking a jury trial when the case ends up in the High Court, probably in 18 months to three years time.

Mr Henry said the Supreme Court had made the standard of proof required by Ms Couch high, "but we've always said we've got no problem matching that".

Ms Couch - who was a part-time accountant at the RSA - suffered serious injuries and spent years in rehabilitation after William Bell wounded her and killed three other employees in December 2001.

She lost 75 to 80 per cent of her blood and spent six months at Middlemore Hospital following the attack. She still has difficulty speaking and now walks with a cane.

Ms Couch had argued Bell was a violent offender and both Corrections and the Probation Service had a duty to protect the public from him.

She said Bell had not been supervised properly and wanted to see someone held accountable for what happened.

- NZPA