Prisoners were being forced to take part in fight clubs by the notorious Killer Beez street gang at Mt Eden prison as early as 2009, and were bashed if they refused.
Prisoners filmed themselves fighting in Mt Eden prison and the videos were posted on YouTube in 2015. Photo: YouTube
Newly released reports into fight clubs at the old and the new Mt Eden prison have revealed the extent of the violence, much of it before private operator Serco arrived on the scene.
Corrections Minister Judith Collins said the reports were appalling and has called her department's behaviour "disturbing".
The Department of Corrections first investigated reports of fight clubs at Mt Eden prison in 2009.
It found the Killer Beez gang was forcing prisoners to fight and staff were turning a blind eye to the violence.
Prisoners told investigators that if they didn't take part in the fight clubs, they would be pack-attacked by gang members later.
Yesterday the department also released a 2014 special monitor's investigation into fight clubs at the new Serco-run Mt Eden jail, which until then it had refused to make public.
It features allegations of savage attacks by gangs, beatings of prisoners by staff, and the deliberate outing of child sex offenders by prison staff to the general prison population.
Prison staff also told the investigators the fight clubs were taking place when there weren't enough staff on the wings.
"It was basically a jungle," said Labour Party corrections spokesperson Kelvin Davis.
He said Corrections did nothing about it.
"The report focused on the making sure that the staff weren't doing anything illegal, but they totally ignore the fact that prisoners were getting their heads punched in. I just think it's institutional neglect."
Corrections Minister Judith Collins said both reports into organised fighting at Mt Eden were appalling, and Corrections had left ministers in the dark.
"Both of them, I think, are really disturbing. And what's really disturbing is that these reports were not elevated at the right time to the chief executive or to the ministers at the time."
In September 2015, RNZ lodged an Official Information Act request for all reports into fight clubs at Mt Eden held by the Corrections Department.
At the time, Corrections said there was only one such report - the 2014 investigation - but yesterday it released the 2009 fight club report too.
Ms Collins said that was not good enough.
"It's completely unacceptable - and it's completely unacceptable that a minister who is held to account for their department does not have access to them."
Mr Davis said everything he had been told by prisoners about violence in prisons had been backed up by the reports.
"They are privileged prisoners that basically run the show and staff just turned a blind eye to it and allowed people to get assaulted at will.
"It just beggars belief, to be honest, that this is going on in New Zealand."
Green Party corrections spokesperson David Clendon said the reports confirms the worst fears about the prison's management.
"Effectively it seems that Serco lost control of that prison, it was an unsafe prison.
"That reality was suppressed for a very long time, and that could have allowed the situation to carry on for much longer than it needed to.
The newly released information also shows Corrections was warned in 2014 that fight clubs were probably being run in Rimutaka and Ngawha Prisons.
The 2014 special monitor's investigation also said inmates had told it of other fight clubs at the other two state-run prisons in Upper Hutt and Northland.
Last month Corrections it said there was no evidence of fight clubs at prisons other than Mt Eden, after inspections in 2015 at eight jails including Ngawha and Rimutaka.