The Irish Nurses and Midwives Organisation says 563 people are waiting on trolleys for admission to Emergency Departments around the country.
The INMO says its a national emergency which must be addressed.
Just before Christmas, Health Minister Leo Varadkar convened an emergency taskforce to find solutions to the escalating problem.
General Secretary of the INMO, Liam Doran, said: "There is always a spike at this time of year. There is no capacity, people have got to understand our acute hospitals, day in day out, are running at what we call 100% occupancy.
"Internationally, it is recognised that if a hospital goes over 85% bed occupancy, it can't function.
"It cannot turn over patients, safely, properly, with pride and diginity. Our acute hospitals have been running at that level for months now."