Four hospitals were not providing healthcare in a clean and safe environment that minimised the risk of infection spreading during the covid-19 pandemic.
HIQA says Mayo and Tallaght University Hospitals as well as Naas and Wexford General Hospitals were not compliant with the standard during its inspections last year.
It's found the Irish healthcare system adapted swiftly to cope with COVID-19, but many facilities were hindered by poor infrastructure and capacity issues.
HIQA’s Head of Healthcare, Sean Egan says some facilities fell short of certain standards.
"In Wexford, Tallaght and Naas, we found problems associated with the approach to streaming of patients - in the context of their presentation to the Emergency Department.
"And the systems and process that were required to separate patients and ensure that staffing in the different areas of the hospital were kept separate to reduce the likely spread of COVID-19."