The officer was one of three assaulted at the Milburn prison in two separate incidents on February 7 and 8, sparking reviews by the regional commissioner.
One of the two assaulted officers taken to hospital has returned to work but the other remains on leave, the Department of Corrections confirmed this week.
Southern regional commissioner Ben Clark said in an emailed statement the reviews into the assaults were ongoing.
The department again declined to present Mr Clark for an interview.
The statement said assaults were regularly reviewed to determine whether they could be prevented in future, but did not provide a timeframe for when the review would be complete.
The assaults last month appeared to be ''unrelated, and spontaneous,'' the statement said.
''The first involved a prisoner in the Intervention and Support Unit (therapeutic unit for prisoners vulnerable to self harm or suicide).
''A prisoner had been asked to clean his cell, and declined before assaulting staff without warning.
''In the second incident, a prisoner had been unlocked to spend time in the recreation yard and punched a staff member in the face, without warning.
''Police are notified about incidents such as these and prisoners involved are held to account for their behaviour.''
The Otago Daily Times last month reported claims of rising violence and tension inside OCF made by a staff member and a recently released inmate.
Those reports came alongside confirmation the number of inmates at the facility reached a record high of 522 in March last year, while 334 were double-bunked as of June 30, before the population began to decline from that peak.
However, Corrections Minister Kelvin Davis said in a recent interview the present population of 466 (as of last Wednesday) remained too high.
Late last month, the ODT also reported on the case of a corrections officer who died by suspected suicide in 2017, days after returning to work at OCF.
Six months earlier, the man was assaulted, sustaining a head injury an ACC psychology adviser found probably resulted in a major depressive disorder and his subsequent death, which ACC deemed to be work-related.
Corrections and Mr Davis declined to comment on the case while it remained under investigation by a coroner.
