The Ulster Hospital has asked members of the public to “consider other options of care”, warning that its staff are facing significant pressure.
It said that Monday had brought an “unprecedented” number of people to the Emergency Department of the hospital, located in Dundonald, at the eastern edge of Belfast.
This, its statement said, had left the department “under extreme pressure” – although steps had been taken in an attempt to free up staff, such as cancelling some outpatient clinics.
Further such cancellations have been made for Wednesday and Thursday.
It said: “We would also urge the public to consider other options of care while the Ulster Hospital Emergency Department remains so busy.”
Belfast’s Mater and Royal Victoria Hospitals both have emergency departments. The one at the City Hospital closed several years ago.