A number of staff at Wheatfield Prison in Dublin have tested positive for Covid-19.
The Irish Prison Service confirmed the development saying that it is "working closely with Public Health, HSE and contact tracing is ongoing".
The IPS said there are no positive cases among inmates in the prison.
However, all prisoners and staff will now be tested as precaution.
The Prison Service said an Outbreak Control Team has been established at Wheatfield "to mitigate against further possible spread of the disease within the prison".