Chief Ombudsman Judge Peter Boshier described the excessive use of restraints as ''cruel and degrading''.
''The effect of being in prolonged restraints becomes a torturous experience,'' he said.
''The length of time in restraints will have caused significant physical and mental distress. The continued and prolonged use of handcuffs to manage an individual's self-harming behaviour is considered disproportionate and unreasonable and amounts to cruel and degrading treatment or punishment for the purpose of the Convention Against Torture.''
In the report, Corrections said the man had ''carried out nine self-harm attempts and had been admitted to hospital on several occasions with injuries as a result of these attempts''.
''The prison director sought multidisciplinary advice on how to manage this prisoner safely and humanely,'' Corrections said.
''This included consultation with the Southern District Health Board's mental health team.
''A carefully considered management plan for this prisoner was created and this included restricted use of waist restraints.''
However, Mr Brooking said the ''shocking'' case showed the department was ill-equipped to manage the health of the prison population, let alone prisoners' mental health.
''That is torture, pure and simple,'' he said.
''If he was that disturbed that they felt they had to have him in a waist restraint and handcuffs for 21 hours a day, he should have been in a mental health hospital,'' Mr Brooking said.
Prisoners were surveyed as part of the inspection; 42% of respondents reported the quality of health services was bad, 62% said it was difficult to see a doctor, and 73% said it was difficult to see a dentist. 69% of those with a physical disability did not feel their needs were supported, and 72% of those with a mental disability reported the same.
''The responsibility of providing health services should be done by the district health board,'' Mr Brooking said.
''That would solve a lot of problems that occur within the prison system.''
Corrections chief custodial officer Neil Beales said the case of the prisoner restrained 21 hours a day was unfortunate.
''What I want to make very clear here is this individual was an extremely, extremely poorly man who was trying to continually do significant harm to himself,'' Mr Beales said.
''[Restraint] was not a means of punishment. This was trying to stop this man killing himself.''
The use of a waist restraint and handcuffs was legal and there was provision for it in the Acts governing Corrections, although it was ''very, very rare''.
Prison staff were left with no other choice because of the risk the man presented to himself. An increasing number of prisoners had some form of mental illness and Corrections was taking steps to improve the quality of care afforded to them.
Staff at Corrections and the prison had learnt from the high-profile deaths of OCF prisoners Boyd Cuttance, Jai Davis and Richard Barriball, who died in custody at the prison in 2012, 2011 and 2010 respectively.
''The inspectors made many positive findings about this prison, such as strong teamwork among staff; prisoners felt they could turn to a staff member if they had a problem; and exceptionally clean, tidy and well-maintained site,'' Mr Beales said.
''Corrections takes its duty of care towards prisoners seriously and is committed to managing all prisoners in a safe, secure, humane and effective manner.
''Prisoners have the right to be treated with humanity, dignity and respect ... therefore there are a number of human rights standards in place to ensure safe detention.''
Many of the recommendations made by the Ombudsman had already been carried out and the department was working to progress others that required action, he said.
The survey
Results of prisoner survey at Otago Corrections Facility. -
32% of respondents assaulted; only 29% reported assaults.
9 inmates sexually assaulted.
45% felt unsafe at some time.
15% felt unsafe at time of survey.
37% victimised by a prisoner or group of prisoners.
68% did not feel complaints were dealt with fairly 84% did not have faith in the complaints system.
43% had children under the age of 18.
72% felt there was a staff member they could turn to for help.
13% not getting their minimum one hour of daily fresh air.
