Corrections sat on a finding that there were fight clubs at Mt Eden prison for a year, partly because the National Commissioner, Jeremy Lightfoot, doubted he could make Serco do anything about it, a report shows.
Mr Lightfoot ordered the inquiry into organised violence at the then private-run prison in May 2014, received its findings by the middle of that year, then did nothing with those for a year until videos of fight clubs were posted on YouTube by inmates.
Mr Lightfoot's inaction is documented in an audit of a 2014 fight club inquiry report, both of which were released yesterday for the first time.
It shows he wanted more evidence after reading the inquiry report, but did not ask for it.
"Additional work should have been undertaken at this point to provide greater certainty as to conclusions and recommendations, given the lack of accessible evidence" from the interviews with reluctant prisoners, the auditors said.
In addition, Mr Lightfoot told the auditors he held back because the report's recommendations could not be implemented, as Mt Eden was at that time a private prison run by Serco and "any ... recommendations were not able to be implemented by Corrections".
Nothing more was done until fight club videos from Mt Eden were posted on YouTube a year later, in mid-2015.
Corrections chief executive Ray Smith said Mr Lightfoot felt the report lacked substantive facts, which came out when the YouTube videos emerged.
However, Mr Smith did not agree that Corrections was unable to require Serco to implement changes Corrections thought were important.
Mr Smith said he proved this ultimately by taking Mt Eden's management off Serco, and forcing multimillion-dollar penalties on the multinational.
Senior managers distracted by fleeing of Phillip John Smith
A 2015 auditor's report also released for the first time yesterday said senior managers at the time were distracted by a major incident - the fleeing of convicted murderer and sex offender Phillip John Smith.
Mr Lightfoot told auditors this escape took precedence and used up all resources.
However, Phillip Smith's escape was in November, four months after the fight club inquiry's initial findings.
Mr Smith defended Mr Lightfoot.
"Oh look, Jeremy Lightfoot has done a terrific job as National Commissioner ... I do have confidence in Jeremy, but he would agree with me that this should have been handled better," Mr Smith said.
"You know, people are human and they don't always do everything perfectly, and you to have to look at things in the round," he said.
Corrections also released a report yesterday that showed there was evidence from prisoner interviews of fight clubs at Northland and Rimutaka prisons.
The department inspected those and six other state-run jails last year and dismissed that.