Four staff were injured and taken to hospital for assessment but were discharged later that day and ''are all keen to return to work'', Miles said.
''They have the full support of prison management and welfare support services, and other staff have been checking on them regularly.''
All four prisoners have been placed on directed segregation and will be charged with misconduct.
Police were advised of the assault and would determine whether any criminal charges were laid.
Miles declined to provide any further information on injuries suffered by the staff members.
''Due to our legislative obligations under the Privacy Act 2020 and the Health Information Privacy Code, we are unable to provide any further information on the staff members at this time.''
Corrections staff worked in a complex and challenging environment with a unique set of risks, she said.
''They manage some of the most dangerous people in New Zealand, many who are highly vulnerable with complex mental health and alcohol and drug issues.
''Assaults on Corrections staff are unacceptable and any prisoner found guilty of an assault will be held to account for their actions.
''As the police investigation remains ongoing, we're not able to comment further.''
Figures released to the Otago Daily Times earlier in the year showed in the 2019/20 year, there were three serious assaults on Corrections officers at Otago Corrections Facility, as well as 10 non-serious assaults, and 21 no-injury assaults.
Corrections recorded health and safety incidents on a tracker system. That included events involving prisoners, staff and contractors, and tracked any injury incidents, non-injury (near miss) incidents and events relating to uncontrolled hazards.
There were 680 events recorded on the health and safety tracker at Otago Corrections Facility between January 1 and November 30 last year.
