Emergency departments are under "unprecedented strain", according to a new report from the Health Information and Quality Authority.
The health watchdog found that in one extreme example, a patient was waiting over 116 hours or 4.8 days for admission to a bed at Limerick University Hospital.
HIQA said it was not uncommon to find patients waiting between 80-90 hours for a bed.
It said that at the extreme end, it found patients waiting to be triaged for care waiting from one hour to three hours and 35 minutes.
The case of three hours and 35 minutes was identified at Mayo University Hospital.
Triage is a preliminary assessment to determine the urgency of a patient's need for care.
HIQA said that if triage is delayed, this poses a significant patient safety risk.
The watchdog found that the factors contributing to the problems are inadequate bed capacity, staff shortages and a lack of access to community services.
In a statement, the HSE said that providing safe, timely and appropriate care to patients is a key priority, with a specific focus on departments experiencing the most difficulties.
It said that a total of 1,228 new acute beds have been funded, with 970 of these expected to be delivered by the end of the year.
The HSE said that among the challenges were a growing and ageing population, Covid-19, influenza and RSV as well as delayed transfers of care from hospitals due to nursing home closures.
Seven emergency departments inspected
For its report, HIQA inspected seven emergency departments that have experienced the worst levels of overcrowding this year.
The hospital emergency departments inspected were Cavan and Monaghan Hospital, Cork University Hospital, Limerick University Hospital, Mayo University Hospital and Sligo University Hospital, as well as in St Michael's Dún Laoghaire and St Vincent's University Hospital in Dublin.
It says that the health system is continuing to see an increasing number of patients attending emergency departments, which is significantly higher than in previous years.
HIQA Director of Healthcare Sean Egan said that overcrowding in emergency departments compromises the dignity and respect of patients and poses a health risk.
The report has four key recommendations.
HIQA said there is an urgent need to build extra bed capacity in both acute and community beds.
It said there was a need to better anticipate and manage staff shortages.
HIQA has called for better leadership at local, regional and national level to deal with the problem.
It also wants improved monitoring of patient safety risks linked to overcrowding.
The report says that the increased attendances at emergency departments is in the context of a growing and ageing population, with increased delays in treatment due to sustained restrictions on non-urgent care throughout 2020/2021 and reduced attendances at general practitioner services throughout this period.
The Irish Nurses and Midwives Organisation said there were 638 admitted patients waiting for a hospital bed this morning.
It said the hospital worst affected was University Hospital Limerick with 75 patients, while there were 68 at Cork University Hospital, 51 at Letterkenny University Hospital and 47 at Tallaght University Hospital.
Assistant Director of Industrial Relations at INMO Limerick Mary Fogarty said the departments are critically under resourced and described the situation in Limerick University Hospital as "groundhog day every day".
She said: "Our members are going into face critical shortages of nurses on the floor and gross overcrowding.
"They have grave concerns for the care of patients which they have raised repeatedly with hospital management.
"These concerns relate to triage and to their own health and safety in the workplace."
She blamed shortage of beds and inadequate stepdown facilities in the community as key factors contributing to the problems outlined in today's report.
"Here in the midwest, this region lost 50 beds over ten years ago and they have never been replaced in the regional hospitals in Ennis and Nenagh. That needs to be addressed.
"There also needs to be further access to diagnostic services in the community rather than admitting patients to hospital."
Stephen McMahon of the Irish Patients Association has called on Minister for Health Stephen Donnelly to urgently reconvene a special meeting of the Emergency Department Taskforce to specifically review the HIQA report.
He said the system must be made safer for patients and trust must be restored in the system's ability to improve the situation.
Additional reporting Teresa Mannion