Goulburn's jail will "return to normal operations" on Thursday, following a brief lockdown sparked by revelations a staff member was a close contact of someone with COVID-19.
Some prisoners were moved into isolation after interacting with the worker, who has since tested negative for the coronavirus.
"Goulburn Correctional Centre was placed in precautionary lockdown today after a staff member was deemed a close contact of a confirmed COVID case," a Corrective Services NSW spokeswoman said on Wednesday night.
"The officer had attended the centre briefly today while transporting inmates to the centre.
"The staff member was directed to go for immediate COVID-19 testing and has since returned a negative result.
"The officer will continue to isolate as per advice from NSW Health.
"The prison will return to normal operations tomorrow."
Authorities had earlier said the Corrective Services NSW "COVID command post" was working with people at the jail to ensure all appropriate precautions were taken.
"The safety of all staff and inmates is our number one priority, and remains at the forefront of our decision-making while COVID-19 continues to pose a risk," the spokeswoman said.
Some of Australia's most notorious criminals are housed at the Goulburn Correctional Centre, which is well-known for its "Supermax" unit.
