Emergency department overcrowding has worsened this summer compared to last summer, according to the Irish Nurses and Midwives Organisation (INMO).

The INMO's latest trolley and ward watch figures have confirmed an 8% increase in overcrowding in July of this year compared to July 2013.

The nurses' union says the latest figures also confirm that many wards, in addition to ED departments, are now regularly overcrowded.

The figures show that during July, 5,535 patients admitted for inpatient care found themselves either on a trolley in an emergency department, or placed on an additional bed/trolley on an inpatient ward.

The INMO says the figures suggest that the health service continues to face ever-increasing demand with greatly reduced bed capacity.

The Organisation says the figures also show that five hospitals recorded huge increases in the number of patients on trolleys this summer compared to the previous summer.

Sligo Regional Hospital recorded a 187% increase in July 2014 compared to July 2013, while the Mater and St James's in Dublin had a 154% increase.

INMO General Secretary Liam Doran said these significant increases represented a major challenge for the health service which it cannot ignore.

"The levels of overcrowding recorded in a number of hospitals during Julyare totally unacceptable, leave patients without dignity and privacy and causes excessive workloads on already overstretched frontline staff," he said.