Tallaght University Hospital has said it is operating its 'Full Capacity Protocol' due to the high numbers attending its Emergency Department (ED).
In a statement, it said: "With high attendances and high rates of admissions this puts pressure on the ED and also the hospital as there is a shortage of beds."
It apologised for lengthy delays and added that there are "long wait times for those who do not need urgent treatment".
The hospital asked people with less urgent complaints to consider alternative care options before attending its Emergency Department.
In its statement, it also said that discharge from the hospital continues to be a challenge with a high number of patients waiting for home care packages or a place in a nursing home.
"The hospital works continuously to free beds for admitted patients," a spokesperson said, "but there is a clear underlying requirement to develop additional onsite bed capacity given our growing and ageing population."