The Irish Nurses and Midwives Organisation has said there are 667 admitted patients waiting for a bed at hospitals around the country.
It said there are 492 patients waiting in emergency departments, with 175 in wards.
The INMO also said 16 children are waiting for a bed at the three main children's hospitals in Dublin.
The hospital worst affected is University Hospital Limerick, with 80 patients waiting, while there are 73 at Cork University Hospital and 71 at University Hospital Galway.
In Dublin, there were 39 patients waiting for a bed at St James's Hospital, with 28 waiting at Connolly Hospital, Blanchardstown and 28 at Tallaght University Hospital.
The Health Service Executive's figures show there were 518 patients waiting for a bed, with 399 in emergency departments and 119 on wards.
The HSE said there were 49 admitted patients at University Hospital Limerick waiting for a bed as of 8am, with 45 at Cork University Hospital and 54 at University Hospital Galway.
