Convicted fraudster Alex Swney has described prison as a "miserable, punitive, negative experience" where gang members rule.
The disgraced former chief executive of Auckland's Heart of the City business organisation opened up during a Newshub Nation special on the justice system.
Swney, who was jailed for five years and seven months in June 2015 after being convicted of tax evasion and fraud involving more than $4 million over a decade, was joined on the panel by criminal defence lawyer Stephen Bonnar QC, Paul Dennehy from the Corrections Association and Lance Norman of Hāpai te Hauora.
Bonnar, Norman and Dennehy all agreed that prison should be about rehabilitation and reintegration into society.
But Swney said that from his first-hand experience behind bars, he saw few signs of rehabilitation.
"It's just a miserable, punitive, negative experience," said the married father-of-two who served most of his sentence at Wiri Prison in South Auckland.
He said it was a place where gangs prosper.
"The place is run by gangs," Swney said.
"This is their family; this is the safety net they have; this is what they know, and so there are a dozen families, a dozen gangs, and they're just all pervasive throughout the whole prison system.
"We need to acknowledge the reality of this. We can't hide behind these platitudes. I'm sorry. The place is broke. We need to fix it up. It starts back in the community. You are not a health worker. There are way too many patients in there, not prisoners.
"Who would blame anyone responding to a gang environment? We're human beings; we cry out for social contacts and connectedness, so it's naïve to break them down. It's better to work with them. Some of the safest wings were where officers were working with constructive gang members and working with a gang rather than against a gang."
Concerns over double bunking and overcrowding was also raised by the panel, which Swney said creates a "dehumanising environment".
He was also dismayed by the lack of visitor time inmates are allowed. Swney claimed he was only allowed 45 minutes a week with visitors, which made it difficult for prisoners to maintain strong whanau and support networks which are critical for a successful release back into society.
His experiences prompted Swney to write to the Justice Minister to highlight the shocking levels of violence and intimidation.
"I used to say I don't need to go to Antarctica to know it's cold. It's cold. But you do need to go to prison to know what prison is like, and if it wasn't so frightening, it would be fascinating," he said.
"It is this unreal environment that you just can't imagine. It attacks you in every way. And I know there'll be people out there saying, 'Oh, look, you've done wrong. If you can't do the time, don't do the crime', but the problem is it's supposed to be something that springboards these people back into our societies — constructive members — and it is doing anything but, because it is such a miserable environment."