Dozens of Victorian prisoners and staff are battling COVID-19 as the state's worsening outbreak leaks into jails.
Corrections Victoria on Tuesday confirmed 39 prisoners and 15 staff are among the more than 14,000 active cases in the state.
Of the infected prisoners, 19 are located at the Melbourne Assessment Prison, 11 are at the Metropolitan Remand Centre, five are at the Ravenhall Correctional Centre, three are at the Dame Phyllis Frost Centre and one is at Port Phillip Prison.
The five COVID-positive prisoners at Ravenhall were in the general prison population but have since been moved into isolation units.
Prisoner movement at Ravenhall has been restricted since September 25 and transfers remain suspended.
More than 900 prisoners have been tested at the prison. A second round of surveillance testing began on Monday, with 749 prisoners swabbed so far.
There are also cases among staff at the Metropolitan Remand Centre (five), Ravenhall Correctional Centre (five), Port Phillip Prison (two), Dame Phyllis Frost Centre (one), Maribyrnong Community Residential Facility (one) and Barwon Prison (one).
"No staff members have been infected with COVID-19 via contact with prisoners," Corrections Victoria said.
"With the exception of some of the cases at Ravenhall, no prisoners have contracted COVID-19 from prison staff.
"All of the other 34 cases have been contained to quarantine and isolation units across the prison system since their arrival and do not pose a threat to the general prison population or staff."
Prisoner movement at the Dame Phyllis and Port Phillip prisons have also been restricted, while all in-person visits to Victorian jails have been suspended for some time.
Zoom and phone calls between prisoners and their family and friends are being facilitated where possible.
Throughout the pandemic, all new Victorian prisoners are tested and required to spend 14 days in protective quarantine, regardless of their COVID-19 risk.
The Community and Public Sector Union, which represents prison staff, said the majority of the infections were at remand or assessment jails.
"This number (of cases) is small and reflects the COVID exposure in the community with prisoners having been transported in from police and court lockups," a spokesman told AAP.
"Thousands of tests have been conducted of both prisoners and officers and 99 per cent have returned negative."
As of Monday, 74 per cent of adults in public and private prisons had received their first dose of a COVID-19 vaccine, and 53 per cent were fully vaccinated.
The first and second dose rates among prison staff are slightly higher, at 82 per cent and 63 per cent respectively.
All staff and prisoners across adult custodial facilities were included in Phase 1b of the national vaccine rollout, which began in late March.
However, on-site vaccinations at Victoria's prisons did not begin until June.