An exclusive Newshub report shows a dramatic drop in serious prisoner-on-prisoner assaults at Mt Eden Prison since Corrections took back control from Serco.
Under Serco's management it was the country's worst-performing prison, dogged by controversies such as fight clubs and drug use among inmates.
Here's what Corrections' numbers show.
- A 55 percent drop in serious prisoner-on-prisoner assaults - that's where, for example, bones are broken or someone needs outside medical attention.
- Less serious prisoner assaults have also decreased on Corrections' watch, by seven percent.
- Serious inmate assaults on staff are static, but low level assaults are up more than 50 percent.
Corrections' explanation is that it's being hyper-vigilant recording every incident.
Corrections has added 84 beds at Mt Eden, but staff numbers are also up 17 percent.
Serco ran a thin roster with "phantom" guards.
And Corrections maintains fight clubs are no more.
"There is absolutely no evidence that there are organised fight clubs," says northern regional commissioner for corrections Jeanette Burns.
But - and there is a but.
"There is fighting on a daily basis in that particular prison," she says.
Thirty percent of inmates at Mt Eden are gang affiliated. Corrections say they are responsible for the majority of scraps.
"If there is any retaliation that needs to be carried out within the prison as per gangs orders, that it is mostly senior gang members asking junior gang members to do that," Ms Burns says.
Prisoners blow off steam at gym class and Ms Burns says Corrections is using extra measures to avoid mixing rivals. Zero tolerance for fighting can mean segregation for prisoners.
Daily prison threat assessments leaked to Newshub provide a rare snapshot of the jail's relentlessly challenging environment.
On one December day two prisoners were caught fighting in a day room.
Another inmate cut open his own arm with a pen casing.
Finds include homebrew hidden in a cordial bottle, three makeshift weapons and a contraband tattoo gun hidden in a light.
January is peppered with reports of fights, some with lookouts posted.
And one described as "contender fighting".
February brought more of the same with reports of grappling, sparring and full-on fighting.
At the end of this month Serco is out of Mt Eden - totally.
There's just a faint grubby mark left where its sign has already been ripped off the building.
But the private operator still runs the 960-bed men's jail at Wiri, in south Auckland.
Newshub.
