Ambulances were diverted from Our Lady of Lourdes Hospital in Drogheda on Sunday afternoon in an effort to relieve the pressure on the emergency department services.
The ambulance bypass was implemented by senior management for three hours while the hospital dealt with a high number of presentations and admissions.
According to sources, at one stage early on Monday, ambulances were waiting over 300 minutes with patients outside the emergency department where there were no beds available.
The bypass was put in place at about 3pm and ambulances were diverted to other hospitals in Dublin, Meath, and Cavan, they added.
The HSE confirmed the temporary move and said there were also visiting restrictions now being implemented for infection prevention and control purposes.
Restrictions include a temporary ban on children visiting unless in exceptional circumstances and one person is only allowed with a patient at any one time. Visitors with any symptoms are being asked to stay away.
It said: "The HSE has advised that the emergency department in Our Lady of Lourdes Hospital remains very busy with a high number of presentations and admissions.
"It is expected that the pressure will continue over the coming days and we would urge the public to use alternative healthcare services for treatment such as GP, GP out of hours, Dundalk Injury Unit and pharmacies when appropriate.
"But if patients are very sick and in an emergency situation they should of course come to the emergency department.
"Emergency departments are always available to treat seriously ill patients and the sickest patients are seen first. People with less severe injuries and symptoms may have to wait to be seen.
"Today, in an effort to relieve the pressure on the emergency department at Our Lady of Lourdes Hospital, senior management implemented a temporary ambulance bypass.
"The ambulance bypass was in place for approximately three hours this afternoon. During that time, ambulances were diverted to other hospitals in the region.
"Our Lady of Lourdes Hospital has also implemented visiting restrictions due to circulating infections, and for infection prevention and control purposes. Visitors will only be allowed in the hospital by prior telephone arrangement with the nurse in charge on the hospital ward."
