The father of an inmate injured at Mt Eden jail says private company Serco has failed to ensure safety at the facility and should no longer be allowed to run it.
This came as Corrections launched an investigation into three incidents that have been made public where inmates from Mt Eden ended up in hospital, the most recent one this week.
Mike Littleton said he and his wife met the Serco prison director in February to voice their concerns about inadequate staffing levels and to question how their son Alex ended up in hospital.
In relation to that incident, Corrections said he was being chased by another inmate and was then injured after falling from a cell block landing.
Mr Littleton said that was not what had happened. He said his son got into a fight in another prisoner's cell but then left and went back to his own cell.
"And they came in with a shank and I don't how many there was, three or four and when he saw that, well that's when he decided he was out of there.
"He saw a gap, took it and he went to jump over the balustrade and as he put his hand on it one of the prisoners came up and whacked him from behind and then pushed him at the same time.
"So he was caught off balance and he landed two floors down and broke both of his legs."
Mr Littleton said they were told the attack continued after he was on the ground. "And there was only one guard there, quite a big fellow apparently, and he was dragging Alex with one arm and trying to fight these guys with the other."
Mr Littleton said he and his wife Lorraine met the Serco prison director on Friday 27 February and were told that while the prison might be short on staff in one area, they would be moved from another.
"Obviously when guys are moving around the cells then you'd think they'd have more guards - obviously they didn't."
Mr Littleton said when he and his wife asked about security cameras they were told by Serco there were none in that area, which they also found surprising.
"It's supposed to be a secure prison so you'd think that everything would be in place to make sure that everyone was seen - if you haven't got guards to watch you should have cameras to watch."
Mr Littleton said Serco should lose the contract for Mt Eden.
Labour MP Kelvin Davis agreed the private operator should no longer have the contract.
"It just goes from bad to worse," he said. "Serco has become a wound the Government needs to cauterize - we can't put up with this anymore, it's just total chaos."
Mr Davis said a criminal investigation should be launched into incidents including the death of a prisoner in June.
He told Morning Report he had been swamped with fresh allegations about incidents about Mt Eden and had yet to go through them all.
"Like I've said before, I'm not naive enough to say that there's no violence happening in other prisons around the country, but the majority of things I'm getting at the moment are about Mt Eden Correctional Facility."
In an email to Serco on 16 February the Littletons said they believed this was not a one off incident as three other inmates on their son's prison ward had similar injuries.
Mr Davis said it appeared Serco had not informed the minister about the email referring to the other cases.
When he asked Mr Lotu-Iiga in Parliament whether Serco notified him of allegations of any similar attacks at the prison, the minister said it had not.
Corrections chief executive Ray Smith said he was taking legal advice and was considering the full range of options with regard to Serco's contract.