Someone who's been there himself says a Parole Board decision to release a killer for a 7th time, will still be a calculated decision.

George Trounson will be released on parole this month, 27 years after beating his flatmate to death in Dunedin.

Psychologist Paul Wood was himself imprisoned for murder when he was 18, and understands the parole process.

He told Rachel Smalley the Parole Board takes its job very seriously.

"I mean clearly he's breached his parole conditions in terms of drinking and that's worrying and concerning. But he wouldn't have been released this many times if he was considered a serious, ongoing risk."

LISTEN ABOVE AS PAUL WOOD SPEAKS WITH RACHEL SMALLEY