The Irish Nurses' Organisation (INO) has warned that more of its members would resign from the A&E at Cork University Hospital if patients continued to be treated on trolleys.
The INO claimed two nurses had decided to step down from their posts since mid-April when Minister for Health Mary Harney opened the new €10.8 million accident and emergency unit.
Nurses have reported patients are lying on trolleys in the new department, which despite being twice the size of the original area only has 12 cubicles.
The INO says members have been forced to work without a promised new transit admissions ward, which was to employ a ward sister and 15 staff nurses.
INO industrial relations officer Patsy Doyle said more nurses would "vote with their feet" if the situation at the hospital was not rectified by management.
"The department is not staffed safely and patients continue to wait on trolleys.
"The lights have been turned down on the grand opening and management has walked away from the deal" she claimed.
Ms Doyle said nurses were left with little choice but to refer the matter to the Labour Relations Commission.
In the meantime, the INO has advised its members at the hospital to sign disclaimer forms stating that they cannot be held responsible for any problems should they arise.
The new A&E unit at the hospital is the only level one type trauma unit in the Republic.
This is based on the department having the back-up of all the specialist services needed to deal with multiple trauma for example neurosurgery, cardio thoracic surgery, orthopaedics and plastic surgery.
The Health Service Executive, Southern Area, was not available for comment yesterday.
However, a spokesman has stated that management at the hospital work continuously with the INO over all issues to do with services at the hospital.