Mt Eden Prison was managed by private company Serco until Corrections took over last month.
Assistant prison director comes to settlement agreement with Serco after being dismissed for serious misconduct.
A high-level manager at Mt Eden Prison refused to take a drug test and was subsequently dismissed by private prison operator Serco.
Darren Farrow, an assistant director at the troubled prison, was suspended and then dismissed by Serco for serious misconduct.
Corrections Minister Sam Lotu-Iiga was advised by Serco of Mr Farrow's suspension on May 14 and subsequent dismissal on July 25.
Mr Farrow, a champion bodybuilder and former soldier who was a key witness in the murder trial of samurai sword killer Antoine Roni Dixon, worked for Corrections at prisons in Christchurch and Auckland before joining Serco's senior management team.
Mr Lotu-Iiga's office confirmed the minister had been advised of Mr Farrow's dismissal and referred further questions to Corrections and Serco, which both said they were unable to comment on individual employment matters.
Mr Farrow said he had recently completed a settlement process with Serco and did not wish to comment.
Serco would not provide any information about Mr Farrow's dismissal.
The company did confirm in a statement to the Herald that its drug-testing protocols included pre-employment, just cause and random testing.
"Refusal to provide consent or undergo a drug or alcohol test assessment when required to do so may constitute serious misconduct, for which a disciplinary process may follow," Serco's statement said.
Serco managed Mt Eden Prison under contract to the Government until Corrections stepped in and took over its operation on July 24 - the day before Mr Lotu-Iiga was advised of Mr Farrow's dismissal.
Serco's management of the prison attracted criticism following concerns over prisoner welfare, including that of 25-year-old Aucklander Nick Evans.
Evans died at Whangarei Hospital following complications in his treatment for pneumonia and a ruptured lung.
Labour MP Kelvin Davis has alleged Evans became mortally ill while being treated for injuries suffered during an assault at Mt Eden.
Three inquiries into his death are ongoing.
Mr Davis alleged there had been multiple instances of prisoners being thrown over balconies, a practice known as dropping.
"You just need to look at the videos that have popped up on YouTube," Mr Davis said.
"The prisoners are in control of the prison, it's just a mess."
Allegations of fight clubs and drug smuggling at Mt Eden on Serco's watch have surfaced and the company has been docked $565,000 for contract breaches relating to prisoner care.
Problems at Mt Eden have continued to come to light since the Corrections management takeover.
It emerged at the weekend that a Serco staff member at Mt Eden had been suspended after being caught fighting an inmate. Footage of the incident was discovered as part of a review into the prison being carried out after allegations of fight clubs between inmates and drug smuggling.
Two members of the Head Hunters gang serving sentences at Mt Eden were recently arrested for their alleged role in a methamphetamine ring. A former guard is also under investigation over smuggled cellphones and other contraband.
And last week a Mt Eden inmate, Liberty Charles Baker, was found dead in his cell. An investigation into the death is under way.
He was a key witness at the trial of Dixon, who was sentenced to 20 years in prison in 2005 for shooting dead James Te Aute while on a P-fuelled rampage during which he chopped off the hands of girlfriends Renee Gunbie and Simonne Butler.
At the time a principal corrections officer at Paremoremo, Mr Farrow testified Dixon had told him of his plan to plead temporary insanity.
Dixon appeared at his High Court murder trial with an outlandish haircut and wild, staring eyes. Mr Farrow, who was in charge of Dixon in Paremoremo's D Block, said he had not seen the inmate's crazy stare before his court appearance.
"He mentioned that he wanted to plead temporary insanity rather than full insanity because he did not want to spend the rest of his life in the Mason Clinic," Mr Farrow testified.
Dixon committed suicide while in custody in 2009.
Key says Serco will have 'all sorts of employment issues' to deal with'
John Key says Serco will potentially have "all sorts of employment issues" to deal with after a review of the Mt Eden prison is complete.
Footage of the incident was discovered as part of the review into the prison being carried out after allegations of fight clubs between inmates and drug smuggling.
The Prime Minister told Radio New Zealand this morning he was waiting for Corrections to complete other inquiries, including reviewing CCTV footage from Mt Eden prison, before any further action is taken.
He would wait for a thorough review before taking any action.
"Obviously we stepped in to running Mt Eden Corrections Facility a wee while ago now ... and they've been working their way through a variety of different issues," he said.
"In the end we'll wait for the Corrections Department to come back and give us a thorough review of what they know and what they think the next best steps are.
"Ultimately they'll have to deal with that through the appropriate mechanism but there will be potential[ly] all sorts of employment issues they'll need to deal with there."
A spokeswoman for Serco, a private British company that was contracted to operate the prison, confirmed an officer had been suspended, pending a disciplinary hearing.
"The safety and security of staff, prisoners and visitors in Mt Eden Corrections Facility is paramount and we have zero tolerance for violence."
The Corrections Department has taken control of the Mt Eden Corrections Facility, which was being operated by private company Serco, following allegations of fight clubs and drug smuggling.
The Prison Inspectorate and the Ombudsman is carrying out a review of the prison after the allegations, and it was during this that footage of the incident involving the now suspended officer came to light.
A spokeswoman for Corrections Minister Peseta Sam Lotu-Iiga said in a statement yesterday that he was "aware of a number of allegations" involving the prison.
"The minister has previously expressed his concern about the allegations and awaits the outcome of the chief inspectorate's review."
Suspension reveals 'systemic problem'
The revelation that a staff member at Mt Eden prison has been suspended after fighting an inmate points to systemic problems, Labour says.
The incident was discovered as part of a review into the prison being carried out after allegations of fight clubs between inmates and drug smuggling.
A spokeswoman for Serco, a private British company contracted to operate the prison, confirmed an officer had been suspended, pending a disciplinary hearing.
"The safety and security of staff, prisoners and visitors in Mt Eden Corrections Facility is paramount and we have zero tolerance for violence."
Labour leader Andrew Little said the revelation was not surprising, because a picture was emerging that showed the prison operation was dysfunctional.
"It does look like there is something systemic there, in terms of the management of it, and it can't go on, and for the sake of public confidence it has to change.
"All this stuff is coming to light because of other people ... as opposed to from the record-keeping by the prison itself. There is a question about how honest they are being in their reporting.
"There seems to be a real question as to whether proper accountability is being maintained, and therefore whether the contract between Corrections and Serco is adequate," Mr Little said.
Reports that a fight involving an officer was captured on CCTV have been denied by Corrections Association president Beven Hanlon.
"My understanding is that there has actually been an allegation of an officer assaulting a prisoner. There have been some preliminary inquiries, which have resulted in the actions that have been taken ... that is not uncommon," Mr Hanlon told One News.
The Corrections Department has taken control of the Mt Eden Corrections Facility from Serco after allegations of fight clubs and drug smuggling.
The Prison Inspectorate and the Ombudsman are carrying out a review of the prison after the allegations, and it was during this that the incident involving the officer came to light.
A spokeswoman for Corrections Minister Sam Lotu-Iiga said he was "aware of a number of allegations" involving the prison.
"The minister has previously expressed his concern about the allegations and awaits the outcome of the chief inspectorate's review." - Nicholas Jones
Serco and Mt Eden
•British-based multinational Serco contracted to operate Mt Eden Corrections Facility since May 2011.
•Allegations extreme prison violence has been allowed to occur on Serco's watch.