Cork University Hospital, which usually has 260 nurses on duty, will have only 70 tomorrow if the nurses' strike goes ahead.
The hospital caters for 30,000 in-patients a year and 110,000 outpatients. It has 550 beds, but it is expected that 90 of them will be closed from tomorrow. If the strike is prolonged, many more beds could be closed, according to the hospital.
Two surgical theatres will continue to work, as will the accident and emergency unit, but unless patients are in life-threatening situations, they have been asked to go to their GP.
According to a spokesman, the nurses' strike committee at the hospital has agreed that once a consultant has determined a patient is in urgent need of treatment, the consultant's opinion will be respected. Otherwise, people will be told to seek alternative care.
The definition of what "emergency care" means has been agreed by the hospital authorities and the strike committee, and includes anything that may amount to a serious threat to life or health, as well as anything that could threaten a patient without immediate clinical management.
Cancer patients from throughout Munster are treated at the hospital, and while there was concern that their radiation treatment might be affected, a spokesman for the hospital said yesterday the treatment would continue as normal.
"Of course people are worried, including relatives and patients, but we have been reassured by the strike committee that they will respond to emergencies. Naturally, these waters are uncharted and we will have to wait and see what transpires.
"We are doing our best to reassure the public that if patients have to come to us, they will get the best possible treatment."
In Tralee General Hospital and the General Hospital in Bantry, the Southern Health Board said efforts were being made to ensure the effects of the strike would be minimised.
An SHB spokesman said: "Management and strike committees have been working on the principle of ensuring patients' safety and covering emergencies. They also worked on the principle of establishing a good liaison between management and the strike committees. Meetings and negotiations are still ongoing. The strike committees are dealing with management's concerns in relation to the contingency plans. Management expects from reassurances received from the Nursing Alliance that necessary cover will be provided."
In privately-run hospitals, such as the Bon Secours in Cork, nurses will not be on strike.