One was fired while two others resigned after investigations into their misconduct, information released under the Official Information Act shows.
It is unclear what led to the departures as the Department of Corrections refused to provide details of the incidents other than the broad categories of misconduct the incidents came under.
Two involved ``behaviour'' and the other was for breaching employment obligations.
The Otago Daily Times requested details of the incidents, but no details were provided, with Corrections providing no explanation for their refusal.
When asked yesterday for further information about the incidents, a Corrections spokesman declined to comment and referred the ODT to the Ombudsman if the matter was to be taken further.
The Ombudsman investigates complaints against government agencies, including issues related to access to official information.
The information Corrections did provide showed three people resigned or were dismissed between July 2015 and June 2016. One person was dismissed in the financial year prior and one person resigned in the 2013-14 year.
Four people also received written warnings for misconduct in the 2015-16 year and one was given a final written warning.
The information showed seven people faced disciplinary action for their behaviour in the five-year period. Seven breached operational procedure, two disrespected the rights of prisoners, two disrespected other staff, one had an inappropriate relationship and five breached employment obligations.
Prison reform campaigner Roger Brooking said the numbers were concerning considering the issues highlighted at the prison by the deaths of Boyd Cuttance, Jai Davis and Richard Barriball. The three men died in custody at the prison in 2012, 2011 and 2010 respectively.
The coroner was critical of prison staff's care for the men.
Mr Brooking said he had seen cultural issues with staff. He believed prison overcrowding had added ``extra stress and strain into the system''.
The latest statistics from Corrections showed there were 465 prisoners in the OCF as at September 30, 2016, up more than 11% on the same time last year.
The prison population throughout New Zealand was up 9% during the same period.
``I don't know if there has been an increase in prison officers but if you have overcrowding, it's inevitably going to lead to other problems,'' he said.
A statement from Department of Corrections corporate services deputy chief executive Vincent Arbuckle, provided with the Official Information Act release, said the department demanded a ``high standard of conduct from all employees''.
``The overwhelming majority of our staff fulfill their duties with integrity and commitment, in what is often a pressured and challenging environment,'' the statement said.
``Any large organisation may encounter a few staff who cannot maintain the high standards set by the majority, and when staff do not meet the standards required of them we take the appropriate action regarding the employee involved.''
Staff were subject to drug testing and stringent checks during the recruiting process, Mr Arbuckle said.
There are 269 full-time equivalent staff at the prison.
