The number of patients waiting on hospital beds remains above 400 today, according to the Irish Nurses and Midwives Organisation.
The organisation says that 302 people are on trolleys while 110 are in overflow on wards.
The latest trolley watch report puts University Hospital Limerick as the most overcrowded with 42 people in need of a bed. Cork University Hospital is next with 40 people on trolleys and overflow areas of wards.
The results come as nurses in a cancer ward at Cork University Hospital begin industrial action over unsafe staffing levels.
A work-to-rule by nurses at the oncology and radiotherapy ward at CUH is to go ahead today after talks between the INMO and the hospital ended this afternoon without resolution.
INMO Southern Industrial Relations Officer Mary Rose said the decision to go ahead with the industrial action was not taken lightly.
The CUH has topped the INMO's trolley watch consistently this year, having previously had the most patients on trolleys in the first quarter of this year.