Convicted double murderer Scott Watson has failed two drug tests while in jail, and has been described as having a very high risk of violently offending again.
Watson recently had his first parole hearing after 17 years of his life sentence for the 1998 murder of Olivia Hope and Ben Smart.
The board turned him down saying he still poses an unacceptable risk to the public.
In its decision the board said Watson had what was described as very uneven behaviour, with numerous run-ins with other prisoners and staff, and he showed a disregard for rules and regulations.
In 1998, while on remand for the murder charges, he assaulted a police officer, and later severely assaulted a fellow prisoner, leaving him unconscious.
In 2001 and 2002 he failed drug tests, and he has been up on misconduct on four other occasions.
The board said in recent times his conduct had improved, and he was compliant and working well inside the wire.
The board received submissions from a number of people, who strongly expressed their belief that Watson was innocent of the crimes. This included Watson himself, who told the board it should take into account an opinion poll showing more than 50 percent of New Zealanders believed he should not be in prison.
The board said those submitters said that because Watson was innocent he should be released from prison. It noted that in one case a submitter said that, if he was not released, it would be covering up the truth.
However, the board said it was not their job to determine Watson's guilt, and it could only determine whether he now posed an undue risk to the community.
A report from a psychologist to the board said Watson had a very high risk of violent reoffending.
It said that Watson's previous offending showed a propensity to violence, an attitude of entitlement and was often connected with use of drugs and alcohol.
The psychologist also mentions that Watson's crimes involved perceived sexual rejection, ruminations upon revenge, and a positive effect associated with inflicting pain and distress.
The psychologist said, given his past behaviour, that should Watson reoffend, he may display a high level of callousness and employ significant efforts to evade detection of further offending.
The board pointed out that Watson had turned down offers to do a treatment programme to address violent tendencies.
Family rejects psychologist's comments
However Watson's father, Chris Watson, said this was because his son would need to admit to the crimes in order to take part.
Chris Watson said he had been optimistic that Scott would get released this time, and the decision was another kick in the guts.
He said he had no doubt that his son was perfectly sane and safe to be out in the community.
Mr Watson said the family may have to look at getting their own psychologist's report done to combat the Corrections Department's reports.
He said his son did have a difficult time in prison early on, but said that was not the real Scott.
"My feeling is that if you are put in with a bunch of crooks and violent people, you are going to have to at least put out an image that you can look after yourself."
The board has declined the application for parole, and said Watson would be seen again in 12 months time - but noted that if there was no realistic progress in treatment, then future hearings may be postponed.