Doctors urge Westminster to "take immediate action" to offset the impact of Brexit on the Northern Ireland Health Service.
The move took place at the Conference of the British Medical Association (BMA).
More than 600 general practitioners have accepted an application recognizing Brexit's "devastating effect" on healthcare in the UK, and particularly in Northern Ireland.
The Ministry of Health in Northern Ireland said it was "aware that this is an uncertain time for all".
It added that "his intensive emergency planning is very important both within the department and within the health and social system".
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Dr. Frances O & # 39; Hagan, who practices in the Irish border area and works in Southern Healthcare, said the insecurity for patients and staff is not good.
"No-deal brexit is an absolute nightmare for us, but even with a deal, we have the problem of recognizing medical professional qualifications," she said.
"This means that for both primary care physicians and their employees, if their qualifications are not recognized, people can not work, which could bring our services to their knees and close our doors on the Monday morning after Brexit."
Dr. Michael McKenna, a GP in West Belfast, said the unknown causes confusion.
"This is very important, we need to know what happens, we have to be organized to deal with all eventualities," he said.
"Take, for example, the transmission of data – these are the medical notes of the people.If someone works in an EU country or is on vacation and becomes ill when he returns to Northern Ireland, we need his notes as notes.
"It can not be that easy to transfer it."
In a statement, the Department of Health said that "no immediate impact on today's provision of health and social care services is to be expected".
It added that "structures and processes were created to deal with potential disruptions if they occurred".
"The safety of people using health and social services is a top priority for the department, and intensive work has been done in collaboration with the Department of Health and Welfare (London) to ensure people get the medicine they need, even then Britain is leaving the European Union, "it said.
Although no Brexit deal was agreed, Paul Laffin, who works for the BMA in Brussels, said GPs are not alarming.
"We do not scare because we've taken the time to question nearly 2,000 EA-qualified BMA members asking them what Brexit means to them, and the answer is clear: it's uncertainty." , he said.
The Royal College of Nursing said that providing medicines was the biggest concern.
"If there were any concerns about taking medicines to Northern Ireland, it would have a major impact on patients, especially on patients who need critical medication," said Rita Devlin, head of career development.
"These patients depend on medications to keep them in a stable state, and if there were interruptions in their care due to lack of medication, those patients could be critically ill and the health service would need to look after them within the hospitals."
Stockpiling, however, may be problematic, according to some sources.
In addition to medicines, other care products may be in short supply, such as the supply and delivery of incontinence pads, which come from outside Northern Ireland.