The prison had 321 men on site as of yesterday.
Acting regional commissioner Glenn Morrison said the reduction in the prison population had eased pressure on the prison network, reducing the demand for beds.
That had provided an opportunity for Corrections to consider moving some men residing in prisons in the Southern Region to newer accommodation that better matched their security classification, and improved their access to employment, education and rehabilitation programmes, he said.
Since its peak of 10,820 in March 2018, the number of people in New Zealand prisons has decreased by more than 20 per cent to 8260.
The move would create the staffing model to enable the new modular units at Rolleston Prison to open, and will allow Corrections to close the Matai, Kauri, and Rawhiti high security units at Christchurch Men's Prison.
Those units were more than 100 years old and no longer able to meet the needs of prisoners and staff.
"We know that providing higher quality, fit-for-purpose environments improves the wellbeing of prisoners and sets them up to make positive changes to their lives.
"In the short term, these units may be reopened if the demand for beds at the site increases, but in the long term they will be decommissioned."
The transfers would also maximise attendance at programmes tailored for high security men at OCF, and programmes tailored for low security men at Rolleston Prison, Mr Morrison said.
The high security prisoners moved to OCF would be able to relocate back to prisons in Canterbury as their security classification reduced, or as they neared the end of their sentence, so they could access programme and training opportunities for lower security prisoners and prepare for reintegration into the community if they would be released into Canterbury.
The decision to move any prisoner would be made on a case-by-case basis, he said.
"Consideration will be given to each man's employment, education and treatment needs and the ability for their family and friends to continue visits with them, as well as how best to safely and securely manage the prison population in the Southern Region.
"The planning for this project is centred around the needs and welfare of the men concerned, and we will work to minimise the number of men who are moved away from their whanau and support networks."
Where men were moved away from their families, Corrections would ensure they could maintain contact through increased frequency of virtual visits, he said.
"We are also working on potential new ways we can support the men and their families to facilitate regular in-person contact."
