Emergency care is "doomed to fail" without an overhaul of the way the local health service is run, a leading consultant has warned.
Dr Paul Kerr, vice-president of the Royal College of Emergency Medicine in Northern Ireland, said the system was coming under increasing pressure as more people attend A&ES and the number of Covid-19 cases begins to climb again.
"Numbers are beginning to rise dramatically in some units, particularly in those trusts which closed units to create dedicated Covid-19 emergency departments," Dr Kerr said.
"This is very concerning at a time when we are witnessing a resurgence of Covid-19 cases.
"We are witnessing prolonged ambulance off-load times and very long waiting times to be seen and admitted.
"These are the most unwell and vulnerable patients who we have a duty to treat in a reasonable time.
"These patients need trusts to urgently improve flow so that they leave the emergency departments after treatment rather than waiting for a day in some cases to get a bed for surgery.
"Patients who have a problem must choose carefully and consider if advice or treatment is available elsewhere. In other words, phone first.
"Also, we are witnessing a rise in the number of patients attending A&E already in the hospital system.
"Patients already under the care of specialists must be allowed to get help without coming through emergency departments.
"The relevant parts to each department of the recently discussed action plan need to be urgently implemented.
"A&E should be a safety net for unwell patients, but if A&E is forced to be the safety net for the whole system, it will fail."
Dr Kerr spoke out after SDLP MLA Colin McGrath demanded reassurances from Health Minister Robin Swann over the ability of emergency medical services to cope with any increased demand.
Mr McGrath, a member of the Stormont health committee, has written to Mr Swann to raise concerns that the Northern Ireland Ambulance Service (NIAS) was five ambulances short on July 29.
He said that at the same time there were no beds available in the Ulster Hospital, while the Royal Victoria Hospital was diverting patients to the Mater Hospital.
Official figures show that more people attended emergency departments at the Royal and Craigavon Area hospitals in June.
It is believed that this is a direct consequence of emergency medical services being scaled back in other hospitals to enable the health service to cope with the continuing coronavirus pandemic.
Health bosses have posted on social media in recent days asking people to only attend A&Es at the Royal, Ulster, Causeway and Antrim Area hospitals in an emergency, due to a high volume of patients.
The Department of Health said increasing demand for ambulances was at present outstripping capacity.
A spokesman added: "Further investment will be required to enable NIAS to respond effectively to present and future demand.
"The department is finalising a review of urgent and emergency care which will inform decisions about the future regional model for services across Northern Ireland."
NIAS chief executive Michael Bloomfield said: "I appreciate the genuine concern of community and political representatives when informed of shortages in a particular area.
"However, I would like to reassure all stakeholders that we will continue to manage our available resources in a way which best serves the interests of patients and staff.
"We would ask you to remember that not all 999 calls require an immediate response and that if you experience delays to please remain patient.
"Our crews will be with you as soon as possible and will treat you with the utmost care, compassion and respect."