According to data obtained by BBC News Northern, some patients in the Western Health Trust wait up to 20 weeks to see a specialist consultant after being flagged.
A red flag referral denotes a doctor's belief that a patient's symptoms require additional research because they could be signs of cancer. .
General Surgery is one of many specialties represented in the inpatient and day case statistics.
The Western Trust has expressed regret.
Other fields affected by this include gynecology, urology, orthopedics, and endoscopy.
The statistics, according to a GP who practices in Londonderry, are "appalling, shocking, and sadly the reality for a growing number of people.". .
According to Dr. Simon O'Hagan, the numbers have "gotten out of control" and are devastating to both patients and medical professionals.
In the Western Health Trust, the longest hospital waiting period for patients in need of orthopaedic surgery is eight years.
According to data from December of last year, some patients have been waiting seven years for an urgent referral to an ENT specialist.
The longest wait for a Red Flag Inpatient/Day Case for General Surgery, according to a statement from the Western Health Trust, is 19.9 weeks, with a 16-week average.
Dr. O'Hagan reported that the Western Trust informed one of his patients, who has been diagnosed with Crohn's disease, that specialists are still seeing patients who have been referred in 2019.
Dr. O'Hagan claims that the patient "has no choice but to self-fund a private appointment for gastroenterology" scheduled for Belfast the following week.
Patients are expressing to us that they simply cannot wait on these lists any longer, claiming that if they do, they will pass away before being seen, he said.
The Department of Health's most recent quarterly waiting-list data reveals an increase of 1,578 since September.
This indicates that 378,411 patients are currently in line for their first consultant-led outpatient appointment.
Additionally, 16,392 patients are awaiting their first appointment for a day-case cataract procedure with a consultant-led outpatient clinic.
According to Dr. Nicola Duffy, a general practitioner in Derry, the average wait time is eight years and 400 weeks.
According to Dr. Duffy, people on waiting lists frequently go to the emergency department (ED) because they are ill and in need of medical attention but for no fault of their own.
Dr. Duffy claims that the lack of accountability regarding waiting lists in Northern Ireland is a contributing factor in the issue.
Colum Eastwood, an MP for the Social Democratic and Labour Party (SDLP), informed the House of Commons yesterday that some of his constituents have been waiting to see a consultant for eight years.
If the "situation can no longer stand and we need a government as soon as possible," did the prime minister agree, he was asked.
Prime Minister Rishi Sunak stated last month that patients in England shouldn't have to wait more than a year to see a doctor.