An academic with experience in investigating complaints from prisoners says the tying of a prisoner to his bed in 2016 was fundamentally wrong.
Research associate at Victoria University's Institute of Criminology, Kim Workman, said it was important that Corrections were transparent.
"It sounds fundamentally wrong that you would have to resort to a meansure of that kind and it will be interesting to see whether it meets the requirements around the protocols in terms of torture and treatment of prisoners."
Mr Workman's comments come as the Ombudsman continues to wait for promised updates from Corrections on a prisoner who is being tied to his bed inside the country's maximum security jail, Auckland Prison at Paremoremo.
The Ombudsman raised concerns about the pisoner in May and was told by Corrections that an investigation was underway and his office would receive weekly updates. Three months on, he has received one update.
Mr Workman said it was time for the appointment of an independent commissioner to oversee Corrections.
"What we actually need is an independent commissioner of corrective investigations that can look at those issues on a systemic basis rather than look at one off issues like this."
He said the commissioner could perform their function in a similar way that the Independent Police Conduct Authority works.
Mr Workman said it was important Corrections were transparent so the public could have confidence that New Zealand prisons met minimum international standards.
Mr Workman, who has worked for Ombudsman investigating complaints against police and Corrections, said Corrections' failure to report to the Ombudsman raises questions about their public accountability.
He said the police performed their role in public and were open to scrutiny. They have also realised the importance of public confidence.
But, he said, Corrections are becoming less transparent by limiting public visiting hours and not replying to Official Information Act requests.
Mr Workman said that was a "recipe for disaster" and if it was allowed to continue, it would encourage unacceptable behaviour.
He said restricting contact and visiting hours also had implications for rehabilitation.
Another example he gave was that prison chaplins were not allowed to continue contact with a prisoner once the prisoner left prison.
He said sometimes a prison chaplin was the only person a prisoner has.
"They're actually putting people in situations where they're actually less likely to stop reoffending"
RNZ contacted Corrections for comment but have yet to receive a response.