Tallaght Hospital has today issued a statement reassuring patients that the facility is safe.
The move comes after some operations and day-care procedures were cancelled at the facility due to seasonally high admittances.
The Irish Nurses and Midwives Organisation says that its staff are concerned about patient care due to overcrowding and staffing levels.
A meeting between management and unions is due to take place tomorrow to discuss the issues.
"Tallaght Hospital is implementing a response plan to deal with the current pressures on the Emergency Department from seasonally high admittances and attendances," the hospital statement read.
"The situation is being fully managed by the hospital and under ongoing review – some cancellations of non-urgent elective and day case surgery have occurred.
"Significant engagement is taking place with the medical and surgical staff in implementing the plan to address the current staff levels and maintain patient safety.
"While this is clearly an undesirable situation, it is not untypical at this time of the year.
"The cancelations are being carried out in planned manner and patients are being notified in advance."
Derek Reilly, industrial relations officer with the INMO said that there is too much complacency about overcrowding in Irish hospitals.
“One patient on a trolley is one too many,” he said. “Not enough nurses – people will die if you don’t have nurses to look after them – that’s a fact.
“You need the medical staff, you need the nurses, and you need the support staff.
“All the management that is happening at the moment is short-term, crisis, sticking a plaster on it.
“There’s no long-term planning in Tallaght Hospital or within the HSE.”
The chief executive of Tallaght Hospital, David Slevin, said that they are currently hiring staff.
"We have a number of recruitment plans in place to try and increase the nursing resource around the hospital," he said.
"We've done a significant recruitment drive over the last period of six months that has seen an increase in nursing staff of approximately 37 whole-time equivalents, that's full-time nurses, since August of last year.
"And we have active plans currently in motion now to try and increase that number again, effective from last Monday."