There are 543 people waiting on trolleys in hospitals around the country, according to the Irish Nurses and Midwives Organisation.
Cork University Hospital is the worst affected, with 46 patients there on trolleys.
The Mater Hospital in Dublin and Midland Regional Hospital Mullingar both have 30 people waiting for beds.
The figures were released this morning, while this afternoon The Mater said it was experiencing very high numbers and protracted wait times in its Emergency Department.
In a statement, the hospital said: "We are asking the public, where possible, to attend their GP in the first instance, or the Rapid Injury Clinic in Smithfield for minor injuries.
"Those attending the Emergency Department will be managed according to priority, so less urgent cases will experience delays.
Overcrowding reached a record high of 612 patients last week.
Meanwhile, the Industrial Relations Officer with the INMO Southern Region has said that working conditions at Cork University Hospital are "intolerable".
Speaking on RTÉ's News At One, Mary-Rose Carroll said there are not enough nurses on the wards to provide the standards of care that patients require.
Ms Carroll said nursing staff are distressed and overworked and the situation is similar throughout the country, making it unattractive for nurses.
"Because the work environment is very very stressful, it's a difficult work environment, and it's impossible to retain staff in that situation. People can only sustain that for a period of time, and eventually they burn out and they move on. And you can't expect them to do anything else."
Earlier, a consultant physician at South Tipperary General Hospital in Clonmel said that the hospital was chaotic and catastrophic yesterday.
Professor Paud O'Regan said it is extremely difficult for staff to work safely.
Speaking on RTÉ's Morning Ireland, he said that trying to apply the same Health Service Executive solutions to each hospital does not work because each hospital is different and deserves an individual solution.
Prof O'Regan said decisions are being made centrally and applied globally, and the policy is not working.
He added that proposals to deal with the crisis, made a year ago, could take at least another year to implement.
The consultant said there is a general lack of beds and explained that elective work is being put on hold during the crisis.
Prof O'Regan warned that the situation will only get worse and it will be almost impossible for elective work to be carried out, which would be an incredible waste of resources and a waste of time for patients.
This meant, he said, that there were consultants in hospitals with no work to do.
