The current outbreak of the winter vomiting bug in Dublin has worsened, with more than 200 patients and staff showing symptoms in one hospital alone.
St Vincent's Hospital reported about 40 new cases of the virus yesterday and said 14 wards have been closed to new admissions.
Some 95 patients and 65 staff have the bug, while another 45 are showing symptoms.
A spokesman for St Vincent's said the hospital continued to be under "increased pressure" and warned that people presenting with minor problems could expect delays.
However, the Irish Nurses' Organisation blamed the problem on overcrowding and "false economies". An official, Mr Philip McAnenley, said that over 30 patients were crowded each day into an A&E department designed for 10 to 12 trolleys; meanwhile, a union request for staff to be provided with surgical scrubs had not yet been met.
"It's a nonsensical situation. We probably can't avoid some cases of the bug, but the problem wouldn't be as bad as it is if we didn't have the kind of cramped, overcrowded conditions it thrives in," he said.
The hospital spokesman appealed to the public not to attend the A&E department if they have the virus, because it could spread to other, more seriously ill, patients.
The hospital has also asked the public to avoid visiting patients "if at all possible"; visits by children are "particularly discouraged".
Visits, where they had to take place, would be strictly curtailed.
Beaumont Hospital said it has three cases of the bug and small numbers were reported in other Dublin hospitals.
However, the Eastern Regional Health Authority said St Vincent's was the only hospital suffering an outbreak.
Two hospitals in the South Eastern Health Board area remain affected.
The Sacred Heart Hospital in Carlow town, where one staff member has the bug, remained closed to visitors and new admissions yesterday. At St Columba's in Thomastown, which has one case, restrictions are in force on two wards.
The Southern Health Board said there were five cases of the virus at Kerry General Hospital in Tralee.
According to the INO, at least 133 patients had to be treated on trolleys in accident and emergency units across the State yesterday.
However, the union believes the real number is higher because figures were not available for four hospitals.
In Dublin, the worst affected hospitals were Tallaght (29) the Mater (26) and Beaumont (20).
Meanwhile, Fine Gael called yesterday for the appointment of a US-style surgeon general to reform the health system.
MEP Mr Gay Mitchell said the surgeon general would have responsibility for assessing the health service and finding more cost-effective measures to ease overcrowding in the system.
