Almost 10,000 hospital patients have gone without a bed so far in March, according to the Irish Nurses and Midwives Organisation (INMO).
Figures from the nursing union's Trolley Watch reveal that a total of 9,856 patients went without a hospital bed this month.
The most overcrowded hospital in the Republic was University Hospital Limerick, with 1,961 patients waiting for beds during March.
That was followed by 1,079 patients at Cork University Hospital and 685 at University Hospital Galway.
INMO general secretary Phil Ní Sheaghdha said March was an "extremely busy month" in Irish hospitals.
"We are still continuing to see a worrying number of patients on trolleys in hospitals across the western seaboard and in the midwest," she said.
“INMO members who are rostered to work this bank holiday weekend are more and more concerned about the ever-increasing risks associated with the provision of services in constantly overcrowded and a progressively under-staffed service.
“The fact is that nurses and midwives will be working short in wards that have significant vacancies due to the HSE recruitment moratorium.”
It comes as the HSE said hospitals were already "extremely busy" ahead of the Easter weekend, and it wants people to stay away unless absolutely necessary.
Anyone who is injured or feeling unwell is being urged to consider a pharmacy, out of hours GP or injury clinic as their first port-of-call.
However, the HSE is stressing that anyone who presents to an emergency department over Easter will be seen and treated, with those most ill and urgent cases being prioritised for care.
Sinn Féin health spokesperson David Cullinane said more money for healthcare, and an end to the HSE recruitment freeze, are urgently needed.
Mr Cullinane told Newstalk radio: "The funding is not there. The Minister for Health of course has to take responsibility, so too does the entire Cabinet.
"If Simon Harris really wants a change of direction in relation to health services, and really wants a spec change, well then the first course of action he should take is to reverse that disastrous decision that was put in place by him and his Cabinet colleagues, to put in place this recruitment embargo."
