Dr Tom Black, NI chair of the British Medical Association, said record numbers of patients were attending GP services.
Dr Black said emergency departments have also been very busy.
On Tuesday, the Western Trust warned there were more than 100 people waiting to be seen at its emergency department and others waiting to be admitted.
On Christmas Eve, Western Urgent Care received 640 calls – up from 158 calls last year, Dr Black said.
Speaking to the BBC’s Good Morning Ulster programme, he said the heath service had been overwhelmed.
“It has been for the last two months,” he said. “Since September we’ve really struggled to keep things going.”
Dr Black said a number of different factors were to blame for the pressures being felt across the health service, including strep A, Covid-19, flu and respiratory viruses and vomiting bugs.
“We’ve seen a confluence of an extraordinary number of infections peaking at this time, all different things – we haven’t seen anything like it before.
“We knew coming out of Covid it would be more difficult but we didn’t expect this to be so severe.”
He said the situation has meant healthcare staff have been forced to prioritise patients.
“I think that’s what we’ll have to do for the next few months,” he added.
“We don’t have enough resources to see everybody with a sore throat or a cough – we’re trying to make sure the most vulnerable and the sickest are being seen.”
The pressures facing the North of Ireland’s health service have been well documented.
In August the British Medical Association warned almost 100 GP practices in the North of Ireland had sought emergency support or were in crisis.
Dr Black said Wednesday is set to be “the busiest day we’ve ever seen” and warned people to only visit emergency departments in an emergency.
“It’s a shared resource,” he said.
“We all pay for this through our taxation and we all understand you can’t be pushing to the front of the queue because you’ve got a sore toe – we have to look after the vulnerable people in our society, particularly today.”
Tags: