The jail's health centre will also be upgraded, as the ACT government implements a key recommendation of a review sparked by the death of an Aboriginal inmate in 2016.

ACT Corrective Services is calling for expressions of interests from private firms to design and deliver a raft of refurbishments at the Alexander Maconochie Centre, as well as an upgrade to the jail's non-compliant sewerage system.

Tender documents, released last week, showed the government is planning a major upgrade of the jail's transitional release centre.

The 'halfway house' accommodates detainees who are due for release, and are currently undertaking daily community work.

The centre's three, five-bedroom wings include communal bathrooms, kitchen and living rooms.

Under the planned upgrade, its existing administration space would be refurbished to accommodate an additional five detainee wings.

A spokeswoman for the territory's justice and community safety directorate, which oversees corrective services, said the expansion was designed to ease "accommodation pressure" caused by a rising prison population.

A record 507 detainees were locked up at the prison in June this year, as average daily detainee rose beyond 470 in 2017/18 - more than double the number from eight years ago.

The spokeswoman indicated the planned halfway house upgrade was separate to a wider upgrade of Canberra prison, which Justice Minister Shane Rattenbury last month said was being considered by the ACT government.

She said announcements about "future infrastructure options" for the prison, including those flagged by Mr Rattenbury, would be made "in due course".

The tender documents also set out plans to refurbish the jail's on-site health centre to include staff accommodation and extra office space.

The spokeswoman said the upgrade would allow for the full rollout of the Winnunga program inside the prison. The implementation of the 24/7 health-care service for Aboriginal detainees was among the key recommendations of the Moss Review, which was triggered by the death of the Indigenous inmate Steven Freeman in May 2016.

Corrective Services is also calling for a contractor to upgrade the prison's sewerage system, part of which was deemed non-compliant by Icon Water earlier this year.

The directorate's spokeswoman said Icon Water had reported that a significant volume of solid waste was accumulating in the sewer pump station downstream of the Hume prison.

A machine to identify and shred solid waste from the system would be installed as part of the upgrade, according to the tender documents.

"The directorate is working collaboratively with the Icon Water to address the issue of non-compliance," the spokeswoman said.

The spokeswoman would not provide details on the cost or timeline for the works, saying they would be determined during the tender process.

The planned upgrades come just two years after the completion of a $47 million, 112-bed expansion of Canberra prison.