The union for prison officers is rejecting a report pointing to the cruel treatment of inmates and people being locked in their cells for up to 23 hours at a time.
Chief ombudsman Judge Peter Boshier paid a surprise visit to Paremoremo prison in Auckland and identified two breaches of the UN Convention Against Torture and a culture of containment rather than rehabilitation.
Boshier found the length of time prisoners were being held in their cells at the country's only maximum security prison prevented any rehabilitation from happening.
Those segregated from fellow inmates were done so in breach of UN rules which said they could not be held in solitary confinement for longer than 15 days.
When inspectors visited the unit, nine had been in there for longer than three months, and two for over a year.
However, Corrections Association president Alan Whitley said if prisoners wanted to be treated differently, they needed to start behaving.
"So how do you rehabilitate a maximum security prisoner who just wants to beat everybody that they get in front of. You can't rehabilitate those people," Whitley said.
"All you can do is contain them until they make a change. You can put stuff in front of them, but you can't make them do it. They've got to want to change."
Boshier found a prisoner was needlessly pepper sprayed when he was following the instructions of guards - the spraying was in breach of the UN Convention Against Torture.
And prisoners in two units reported bullying and intimidation by staff, with accounts centring on several of the same prison officers.
Whitley insisted his members were doing their best but were dealing with some of New Zealand's most hardened criminals.
"He is all good at making recommendations of how things aren't happening but he's not good at making any recommendations over the tools that we need to be able to keep the staff safe while we're doing it. And staff safety is paramount. They don't go to work to be assaulted."
Academic and former Wellington Howard League president, Christine McCarthy, said the prisoners were stuck in a vicious cycle.
"If you're locked up in solitary confinement, there are physiological problems. And it's really difficult to manage people if they become delusional, you've got a situation which is only going to make matters worse, and that's where we've got to kind of pull the plug on what we're doing and we have to actually make quite a significant change."
The ombudsman's report was published after an initial visit at the start of this year and a follow up two weeks ago to see how many of his recommendations had been actioned.
He noted that change had yet to occur.
McCarthy said that was not surprising.
"Each prison has a leadership and a management and a very different culture. And it's an enormous difficulty. To be honest, prisons are hidden from the public. They're not going to change until the public demand change."
Boshier said the problems at Auckland Prison were despite $280 million being spent on it just two years ago, with the express aim of it moving towards doing a better job of rehabilitating prisoners.
"This was supposed to be the prison that dealt with New Zealand's hard criminals in order to try and rehabilitate. It's sadly not doing it. It really is just containing and not really achieving the goals it was set out for. So big challenges ahead, strong leadership needed."
RNZ was keen to put these concerns to the leadership at Corrections.
Its chief custodial officer, Neil Beales, was not available to be interviewed but did have time to write up a long statement saying his department had accepted 33 of the Ombudsman's 37 recommendations, and had partially accepted four of them.
"As New Zealand's only specialist maximum security facility, our staff at Auckland Prison are managing the most dangerous and difficult prisoners," Beales said in his statement.
"It's a challenging job, and one that is essential to protect the safety of all of our communities.
"We are constantly working to ensure our prisons provide the safest environment possible for staff and prisoners, and that the public are protected."
His boss, Corrections Minister Kelvin Davis, was also not willing to be interviewed.