There has been a 7% rise in the number of people waiting on trolleys in hospitals across the country.
The latest Irish Nurses and Midwives Organisation (INMO) figures show 7,392 patients were without hospital beds in June.
Last Tuesday, 482 patients were on trolleys, the highest total for any day in June since records began.
The trolley watch figures show of the 7,392 patients waiting for beds were 55 children.
The worst hit hospitals for June were:
INMO General Secretary Phil Ní Sheaghdha said: "Our members tell us that there’s no longer a summer respite when it comes to overcrowding.
"Summer 2019 is as bad as winter was five years ago. Understaffing is driving year-round unsafe conditions.
"The government and HSE need to get a handle on this problem.
"That means implementing the Safe Staffing Framework and making real progress on Sláintecare.
"Without serious investment and reform, this problem will continue to spiral, with patients and frontline staff paying the price."
The news comes as the INMO revealed last Friday that there has been 279 assaults in HSE hospitals in 2019 so far with 89% of them against nurses.
Ms Ní Sheaghdha said the figures are just the tip of the iceberg.
"Many more assaults go unreported, as nurses are often too busy to stop work and do the paperwork. The statistics also do not include voluntary hospitals, where problems are likely just as bad.
"Overcrowded, understaffed services create a pressure cooker environment. Patients can get frustrated at conditions and a tiny minority unacceptably lash out at staff.
"That means frontline staff being put at risk for conditions they are not responsible for."