There are 654 patients waiting for admission to a bed today, according to figures from the Irish Nurses and Midwives Organisation.
The hospitals most affected today are University Hospital Limerick with 73 patients waiting, Cork University Hospital with 59 and University Hospital Galway with 49.
The HSE figures put the number nationally at 472.
Yesterday, University Hospital Limerick said it had reduced elective surgical activity and increased ward rounds, in order to identify patients suitable for transfer or discharge.
Separately, Children's Health Ireland, which represents the three main Dublin children's hospitals, said that over the weekend it had seen an increase in the number of young children and infants presenting to their Emergency Departments.
It said that the increase in numbers is due in part to more cases of the winter vomiting bug.