Nearly 1,000 patients were admitted to hospital without having a bed to go in last month, according to figures released by a nursing union.
The Irish Nurses and Midwives Organisation (INMO) said 9,091 patients were admitted on trolleys or into overcrowded wards in May.
This is the highest figure ever recorded for this month compared to previous years, a group spokesman said.
University Hospital Limerick (858) and Cork University Hospital (826) were the two highest recorded in May, according to INMO.
At University Hospital Waterford the figure was 329, down on last year’s high of 412.
Nationally, the figures show an overall increase of 12% on the same period last year when 8,154 patients were admitted waiting a bed, it is claimed.
Some 92 children waited on trolleys in Dublin’s three children’s hospitals, the union also said.
INMO General Secretary Phil Ni Sheaghdha said the “constant and worsening crisis” could not wait until the winter for funding when the “escalating” problem would be “out of control”.
She said: “We live in a society which expects a long wait, and a lack of privacy and dignity when attending EDs (emergency departments). It is not acceptable.
“It is a basic human right that a person deemed as requiring hospital admission is admitted to a suitable bed which is appropriately staffed.”
She called for better planning to avoid patients having to be left waiting on corridors.
A Department of Health spokesman said: “The Government is and will continue to provide increased resources to address the situation in the face of rising demand.
“The HSE TrolleyGar figures are showing that for the first four months of 2018, there was a decrease in trolley number of 16.9% or 301 less patients on trolleys as compared to the same period in 2017.”
– Press Association