People are being urged not to attend the emergency department at University Hospital Limerick unless it is necessary due to the high number of patients there.
In a statement the UL Hospitals Group said that 232 patients attended the department from 8am yesterday to 8am today.
The statement said the hospital was managing high volumes of patients following a busy weekend in the department and a rise in the number of delayed discharges across the group.
Members of the public are being urged to consider attending the injury clinics at St John's Hospital in Limerick, or at Ennis and Nenagh hospitals, instead of UHL.
Figures from the Irish Nurses and Midwives Organisation show that 78 patients are on trolleys at UHL waiting admission to a hospital bed.
The INMO said there are a total of 451 patients on trolleys in emergency departments or on wards in hospitals around the country.
The other hospitals worst affected are Cork University Hospital with 46 patients on trolleys and 36 in University Hospital Waterford.