A case of measles has been confirmed at the Mt Eden Corrections Facility.
Deputy National Commissioner Andy Milne said on Saturday evening one prisoner was confirmed as having measles after showing symptoms the day prior.
The prison contains nearly 1000 prisoners, with a further 500 staff working at the prison.
"The prisoner was immediately isolated on Friday, along with another prisoner that he was sharing a cell with," Milne said.
"This prisoner does not have any symptoms of measles. The unwell prisoner had not been escorted out of the prison, or received visitors during the exposure period."
Corrections immediately made contact with Auckland Regional Public Health Service, and remains in regular contact with them, Milne said.
On the advice of Auckland Regional Public Health Service, the following steps were being taken to reduce the risk of any infection spreading.
• Only staff who are immune are working with the two prisoners who are currently isolated, and in a two further prison units where they had been during the past week.
• Prisoner movements in and out of the two units have been restricted. All Court appearances for these two units will be carried out by Audio-Visual Link, or deferred.
• Visits and programmes for both units have been temporarily suspended to ensure the health and safety of both visitors and contractors. Visits from under fives and pregnant women were temporarily banned site-wide.
• Serology testing has been arranged for staff and prisoners in the two units to determine their immunity status in cases where this information is not already known.
• Staff were proactively monitoring all prisoners on site for any symptoms of infection.
• Personal protective equipment (including masks and hand sanitiser) has been provided to prevent the risk of infection from spreading.
"Again, we remain in regular contact with Auckland Regional Public Health Service which advises us that there is an average of six confirmed cases of measles in the Auckland community each day," Milne said.
"The secure and controlled nature of the prison environment means we have been able to quickly isolate the unwell prisoner, restrict movements, and identify those on site who would have been in contact with this individual."
Following serology testing, if a prisoner is found to be non-immune, they would be placed in quarantine, he said.
"If a staff member is found to be non-immune, they will be required to stay at home in quarantine. This quarantine period for both non-immune prisoners and staff will be two weeks from their last contact with the unwell prisoner."