More than 12,000 patients are on waiting lists for appointments at Mayo University Hospital.
The stark figures were revealed to Independent councillor Michael Kilcoyne at a meeting of the Regional Health Forum West meeting.
A total of 4,979 people are awaiting outpatient appointments at the Castlebar hospital and 1,923 inpatients are waiting to be seen.
“These waiting list figures are extremely serious,” said Cllr Kilcoyne. “What’s even more frightening is that there are people who have had a procedure carried out and they’re waiting three years for a review,” he added.
The Independent councillor fears that Covid-19 will create an even longer backlog.
“It’s going to get bigger. The number of people on the waiting list is nearly the same as the population of Castlebar and nearly three times the population of Westport.”