Some elective procedures have been postponed because of "pressure" and "lack of bed capacity" at Letterkenny University Hospital (LUH), Co Donegal.
A Saolta spokesperson said LUH Emergency Department is "extremely busy with high numbers of people attending the Department who need to be admitted to hospital for ongoing treatment."
They added that "all available beds in the hospital are in use."
Some 171 people attended the Emergency Department yesterday and the hospital is seeing similarly high numbers today.
There are currently 66 patients in the Emergency Department with 23 patients waiting to be admitted.
Patients are facing long waiting times to be admitted from the Emergency Department to a bed on a ward.
LUH is advising that patients who attend ED for routine and non-urgent treatment will experience very long waiting times.
The spokesperson said: "Every effort is being made to discharge patients who are ready to go home so that beds will become available for patients who need to be admitted, at the earliest opportunity."
The added: "Due to the pressures on the site and the lack of bed capacity, the hospital is postponing some elective procedures.
"Urgent, time sensitive cases are being prioritised.
"Patients are being contacted directly if their procedure is being postponed."
The hospital says people who do require emergency care are encouraged to attend the Emergency Department where they will be prioritised. They have acknowledged these delays are "very difficult for patients and their families and apologises for the inconvenience and distress these delays cause."
People are asked to attend their GP or out of hours service in the first instance if at all possible.
