The Mater Hospital is under investigation after more than 200 Covid-19 cases were reported to the Department of Health yesterday.
This follows an announcement made by Dr Tony Holohan yesterday when 426 cases were confirmed but a large number of the cases were not new.
The Mater Hospital reported 244 cases in one day but they date back as far as mid-March.
The hospital stated that all confirmed cases were reported to relevant authorities on a daily basis.
The hospital is now working with the HSE to understand why this happened.
The HSE have stated that they are currently not in a position to confirm if the hospital reported the cases.