The gunman who shot dead six people in the Raurimu massacre in 1997 has spoken of the events that led to the tragedy and apologised publicly for the first time.

"Am I sorry for what has happened? Yes, I am," Stephen Anderson says in an article he wrote for the latest North & South magazine.

Anderson describes his upbringing in a loving family, the lead-up to the killings, his mental ill health and what it was like locked up in a psychiatric facility after he was found not guilty of murder by reason of insanity.

The 38-year-old said he regretted about half a dozen incidents in his life, "none more so than shooting dead my father, Neville, and five of his friends and associates".

"As well as the pain in my own family, my actions have affected a great many others."

Anderson, who is back living in the community, said he was now doing better, and while he understood the concerns people might have, he did his best not to cause harm to anyone. Nor did he want to upset anyone.

"The last thing I wish to do by writing this article is to cause more harm than has already occurred. I have done my best to keep the best mind possible through this process."

Isabel McCarty, who was shot in the back by Anderson and lost her husband in the killing spree, said she hadn't decided whether to read the North & South article.

Anderson's remorse, however, was "too belated" to make any difference. "I think he's trying to make himself look good."

David Van de Wetering - whose father Henk was killed and brother Rodney wounded in the massacre - said he had no interest in what Anderson had to say and wouldn't be reading the article.

"The damage he's done has been done. I don't think there's ever going to be any closure on it. To me, it's just heart-sobbing bullshit that he's going to make money off ... while everyone else is still struggling to live with what he created."

Anderson - who was paid a freelance contributor's fee of around $2500 for the article - wrote that he had a "charmed" childhood and came from a "clean Christian household".

"I knew my parents loved me and I loved them back."

While he doesn't talk about the actual killings, he describes how he was "in another world" in the lead-up to them.

He said his cannabis use and failure to take prescribed medication for mental health issues - "I didn't believe I was unwell" - were common-sense observations of what caused his actions and were valid criticisms.

"At Raurimu, I was very unwell. I do not blame anyone for what I did, and I now have an acute sense of how I must take responsibility for my mind and the actions that come from it."

When people say he must have known that what he was doing was wrong, he replies: "Yes, I could see others might have that view of my actions but I didn't see it that way. My mind was labouring under a psychosis that convinced me the future of the world was at stake and my failure to act would most likely meet with a most dire outcome for all sentient beings."

Anderson describes his first few months in a medium-secure forensic unit and how he had to earn privileges such as wearing his own clothes instead of hospital pyjamas.

"It is quite a challenge to lose your freedom and possessions and then enter a period of long-term negotiation to reclaim as much autonomy and responsibility as you can."

After spending the first seven years after the killings in lock-up units, Anderson spent the rest of his time "looking after myself and trying to help others in the hospital environment or in the community".

He believes people can be "treated and successfully reintegrated into the community" but knows there are concerns about his living back in society.

"While it is true that I have a controlled degree of liberty, I try not to cause harm through any action I take - not always successfully, it seems - but I bear no ill will towards anyone, living or dead, who has been affected by what I have done."

He said he still had symptoms he had to manage, like "struggling with an angry mind", but was thankful for the support of his mother and believed that if it hadn't been for her, he would not still be alive.

"When I think about what I've done, I sometimes quietly shake my head, and yet many still care and make loving and comfortable accommodation for me in their lives."

* February 8, 1997: Stephen Anderson shoots and kills his father, Neville Anderson, and five others - Andrea Brander, Anthony McCarty, John Matthews, Stephen Hanson and Henk Van de Wetering - at the family's ski lodge in Raurimu, 34km southeast of Taumarunui. He wounds four others.
* The paranoid schizophrenic was found not guilty of murder by reason of insanity in December 1997 and became a special patient at a secure unit at Porirua Hospital.
* Released from psychiatric care last year. Living in Upper Hutt.
* The Raurimu massacre is among the top five worst mass killings in New Zealand history - the others are Aramoana and the Schlaepfer, Ratima and Bain family tragedies.