A Corrections Department investigation at Rimutaka Prison in Upper Hutt has found support for allegations of corruption and prison officers smuggling contraband to inmates.
Chief executive Barry Matthews said the claims were serious and, if they were substantiated, police would become involved and guilty parties would be dismissed.
"We've had some staff come forward with a degree of support as to contraband getting into the prison, and the only way it could have got in under certain circumstances would be for a member of staff to have done that," Mr Matthews said.
"We are uncovering some things and I would expect we'll be taking action against a few individuals."
Last night Corrections Minister Damien O'Connor said the allegations were the most serious faced by his department.
"I am determined to verify these claims and to root out any forms of corruption at any level at any prison."
A former Rimutaka prison officer, Andy Coward, has told of a culture of corruption and fraud in the high-security segregation unit where he worked.
He said not all staff were corrupt, but nearly everyone knew that prison officers were the main conduit for smuggling contraband.
"In any of the high-security units, there's very little chance of getting stuff in other than through staff," said Dr Coward, who has a PhD in cognitive psychology but was not employed as a psychologist.
He said prison officers filled in documents for cell searches that were not done, and the unit was filled with contraband.
"Prisoners were never short of stuff. There were some, as quickly you take stuff off them they'd have more. I've never seen anything like it."
Dr Coward's claims mirror those of former prison officers Mark and Ingrid Rijniers, who worked in a different high-security unit.
They said staff there were at the mercy of gang members.
An independent investigation is looking into the claims. It was set up last year after Mr Matthews told Parliament of an "unhealthy culture" at Rimutaka.
Corrections would not say if any Rimutaka staff had been dismissed for smuggling contraband, or how many were being investigated.
Since July 2002, four officers in Wellington jails - including Rimutaka, Arohata and Wellington Prison - have resigned while being investigated for smuggling contraband.
Nationwide, four prison staff have been dismissed and nine suspended in the past two years for smuggling contraband.
Mr Matthews said the figures represented a few bad apples.
"We're talking probably about five in the whole organisation. That small number do tremendous damage, and they damage the reputation and trust of all staff and the organisation as a whole."
The investigation was progressing despite a lack of co-operation from Dr Coward and the Rijniers, who do not trust Corrections.
Mr Matthews said support for the corruption allegations had come from existing prison staff.
"If we identify staff that have been acting corruptly and in a criminal way by bringing in drugs and so forth to prisoners, not only will police be involved but we'll also take action to remove them from our services as quickly as possible."
