An independent investigation has found concerns about a 'boys club' culture among the managers of an Otago prison.

The Office of the Inspectorate inspected the Otago Corrections Facility in Milburn, south of Dunedin, last September.

In a report released on Tuesday, chief inspector Janis Adair said, while there were many positive practices at the prison, staff described the leadership team as a 'boys club'.

Concerns included bullying, inappropriate and misogynistic comments by managers and staff, disrespectful behaviour towards women, and offensive sexual remarks by prisoners being ignored or unchallenged.

The report recommended an urgent review and reset of the senior leadership team culture.

Adair said the Otago Corrections Facility had developed an action plan to address the findings and she would continue to monitor its progress.

The Department of Corrections acknowledged the findings and said it had a nationwide programme underway to eliminate sexual harassment.

The site had 527 prisoners and 358 staff, mostly custodial, at the time of the inspection.

The report found the jail had a wide range of activities and opportunities for prisoners, responsive and helpful custodial staff, and a clean and well-maintained jail.

The leadership team had a clear strategic plan with a focus on rehabilitation, nursing staff were described as supportive, approachable and generally doing a good job in managing day-to-day health needs, and self-care units provided excellent re-integration opportunities, the report said.

"Inspectors observed positive interactions between prisoners and staff in all areas of the site," the inspectorate said. "Staff were calm and used appropriate language when speaking to prisoners."

The report noted a collaborative approach to managing prisoners with mental health need, and in the intervention and support unit.

The inspectorate said there was high use of two dry cells at the prison, but it was unclear why.

"We could find no records that explained the reasons it was necessary to deprive the person of a toilet, running water and privacy screen."

The inspectorate found prisoners had safety concerns about cell sharing and reported long wait times, often several months, to see a dentist that meant some teeth deteriorated to the point they needed to be pulled, rather than earlier intervention, including fillings.

During the inspection, the inspectorate noted prisoners were strip-searched, instead of using a body scanner, before court appearances and transfers.

Department of Corrections custodial services commissioner Sean Mason said the department was committed to continuous improvement.

"Over 30 percent of our 11,000 staff have completed our understanding sexual harassment training, which helps staff recognise harmful behaviour, understand what's not acceptable and see their role in creating a safe workplace," he said.

"The site is committed to taking deliberate and sustained action, recognising that even isolated experiences can have a significant impact on individuals and must be addressed."

That included all managers and principal corrections officers already completing online sexual harassment training and staff workshops in July.

"Creating and maintaining a safe, respectful and inclusive workplace is a fundamental expectation, and any behaviours that fall short of this are not acceptable," Mason said.

"While feedback to the inspection team reflected a range of perspectives from staff, including many positive views of leadership and workplace culture, we recognise other concerns.

"In particular, the issues identified relating to inappropriate comments, culture and the need to consistently challenge offensive behaviour from prisoners highlight areas where greater consistency and visibility of expectations are required."

Mason said the report outlined many examples of positives practices at the prison and the department looked forward to continuing to engage with the inspectorate.

In response to concerns about dry cells, Mason said they were used during the inspections, when bed capacity in the intensive supervision unit was limited, more transfers needed mental health assessments and one patient needed time in the dry cell "to ensure they were kept alive", which was documented in his management plan.

He confirmed the department had asked staff to prioritise the use of body scanners where possible and limit strip searches, which would be closely monitored.

More staff had been hired or were being recruited to ensure the case management team was fully staffed.

An additional mental health position had been established internally at the prison and existing services had been streamlined to improve access to psychologists, Mason said.

A previous inspection report published in 2019 found the prison worked effectively with relatively few issues, but was operating close to full capacity and that prison population growth was a challenge.