By Kim Vinnell
Private prison operator SERCO is coming under increasing pressure following claims guards in Mt Eden Prison are encouraging organised fight clubs.
It has now been revealed both the Corrections Department and SERCO knew about the clubs 18 months ago.
The fights happen in one-minute rounds.
Sometimes it is gang prospects trying to get patched, other times it is a way to earn a reputation.
3 News met one former inmate who says guards turn a blind eye to fights, which on the inside are called "contender battles".
"Some of it is one gang versus another, other times it's internal gangs sorting out differences… or just simply entertainment," he says.
SERCO has been plagued by allegations that its attempts at cost cutting could put lives at risk.
The prison is struggling to find and keep staff, and topped a list for the number of prisoner assaults in the three years to 2014.
Several inmates have told 3 News the guards not only allow the fights, but actively encourage them by putting rival gangs in the same block and sometimes placing bets.
In a statement, SERCO says it is working with Corrections in its investigation, but goes on to say that for many prisoners violence is the norm.
Corrections denies guards are involved, but admits it knew about the fight clubs 18 months ago.
It says back then it could not find enough evidence to warrant a full scale investigation.
Community advocate Richie Hardcore says this should be a wakeup call for lawmakers.
"Eighty percent of people in prison were under the influence of alcohol or other drugs at the time of their offending," he says. "You have to look at the environment and the context."
SERCO's contract is up for renewal in 2017, but Corrections is hinting that it is reviewing its contractual obligations.