Emergency departments remain 'extremely busy' with increasing numbers of children and older, sicker people with complex conditions attending and being admitted.
The Health and Social Care Board paid tribute to staff who are "working tirelessly to ensure that patients receive the care that they need".
“However, as predicted, the pressures on services have led to some patients waiting longer than is acceptable.
“We would therefore ask the public to assist us in using services appropriately. Our clear message is if you are seriously ill or injured, then the Emergency Department is the place to go.
“If you are not assessed as urgent you may have to wait for a lengthy period," said a spokesperson for the HSCB.
SDLP health spokesperson, Mark H. Durkan MLA, has said that escalating waiting times in emergency departments were a symptom of a health service in crisis
He said: “It is nothing short of an outrage than 300 patients waited more than 12 hours in emergency departments. This is yet another reminder, if it were ever needed, of how badly our health service needs transformation and investment.
“Our health care workers across the North are working under extreme pressure and are at breaking point. These escalating waiting times and the numbers of patients waiting are in the context of looming industrial action next week, where health workers are striking for pay justice.
“The inability to get people out of the hospital and into their homes is also contributing to these delays and any future Health Minister must consider care packages as part of the discharge process. These figures are also a result of increasing pressure in primary care and people being unable to get a timely appointment at their GPs surgery.”
A spokesperson for the HSCB said: “If you do not need emergency care, we would urge you to please choose alternative services. These include using the online A-Z symptom search , seeking advice from your local pharmacist, contacting your GP, or the GP Out of Hours services (if your medical condition can’t wait until your GP surgery reopens).”
“The public can access waiting time information at all EDs and Minor Injury Units across by logging onto www.nidirect.gov.uk/emergency-department-waiting-times. This NI Direct webpage is updated hourly.”