Prisoners say they're victims of sexual abuse and serious assault by the men and women who are supposed to be guarding them.
1 NEWS can reveal that prisoners made 16 complaints of sexual abuse and 15 complaints of serious assault against Corrections staff between 2012 and 2016.
Ten prisons face allegations including Paremoremo, Christchurch Men's, Hawke's Bay Regional, Mount Eden Corrections Facility, Rimutaka, Spring Hill Corrections Facility, Tongariro, Waikeria and Whanganui. A serious assault is alleged to have taken place at a court house, which has not been identified.
1 NEWS first asked for the information in September 2016 but was declined by Corrections on the grounds that "it did not exist in a form that could be readily supplied".
A complaint was then made with the Chief Ombudsman Peter Boshier, who told Corrections that it should not have refused the request by 1 NEWS, "particularly where information could not be provided due to a lapse in Corrections record keeping".
1 NEWS had also asked and was again declined by Corrections for the number of allegations that progressed to an investigation, the number of complaints upheld and the number of staff subject to a complaint who are still employed.
Mike Williams from the Howard League for Prison Reform said there needs to be greater transparency.
"These people are incarcerated, they're not free and therefore their ability to complain and to have something done about it is absolutely critical," Mr Williams said.
"We don't know whether this process is working because it's not being properly tracked. Let's see it properly tracked," Mr Willliams said.
Corrections chief custodial officer Neil Beales said the lack of oversight was only noticed when 1 NEWS raised questions.
"There's no question in our mind that any incident hasn't been properly investigated because we know we've got very good HR processes. What we're talking about here is the actual collation of that," Mr Beales said.
Corrections is now reviewing its notification process for prisoner complaints and is developing a more comprehensive case management system for employment investigations, with information gathered and held at head office.
Mr Beales points to the 2015/16 financial year where 22 staff members were dismissed from Corrections, saying it shows "we do hold people to account".
Again, Corrections can’t say why those staff were let go but is promising the information will be available later this year.