"I wouldn't like to see him out and about in the community again," he told the Bay of Plenty Times.
"I would prefer he wasn't out, but if he is out I definitely believe it needs to be supervised outings.
"Back then I believed he would reoffend if he was let out and I have the same feeling now."
Coulam dragged Miss Cantwell into bushes and strangled her as he raped her, leaving her lying semi-naked about 50 metres from the track.
Police found her three days later, after friends reported her missing. Coulam was arrested soon after.
Before killing Miss Cantwell, he shocked flatmates by telling them he had been fantasising about strangling a woman as he raped her.
When he arrived home after being away for a week and boasted about being responsible for Miss Cantwell's death, his flatmates called the police.
In December 1989, he was convicted and sentenced to life in prison.
In 1996, Coulam was diagnosed with schizophrenia and transferred from prison to a mental health facility.
A court order made Coulam a special patient under the Mental Health Act, meaning he had to remain in a secure mental health facility indefinitely.
For the past 17 years, the Department of Corrections has had no responsibility for Coulam and even the Parole Board cannot stop him being released into the community.
He became eligible for parole in 2011 but was refused on the basis that he still posed a risk to public safety.
Now 43, he appeared before the board again in January.
A Corrections spokeswoman said that as a patient at Auckland's Mason Clinic, Coulam was legally under the care of the Waitemata District Health Board.
Corrections would take responsibility for him only if he was transferred back to prison.
Coulam is technically still a "prisoner" so, by law, his case must still be considered by the Parole Board.
But because of his patient status, his supervision and treatment are managed under mental health legislation - which is outside the board's jurisdiction.
