More than a half a million people are now on public waiting lists.
New figures reveal that 536,000 people are in queues nationwide for surgery, outpatient appointments or endoscopy procedures.
With numbers on trolleys in the emergency departments of hospitals reaching record levels last week, hundreds of patients on outpatient waiting lists, who have been in the queue for over a year, have been told that their operation is being cancelled due to overcrowding.
The 2016 end-of-year waiting list figures have fallen slightly for the first time in two years.
A survey by the Irish Independent yesterday showed some of the hospitals worst-hit by overcrowding are cancelling operations already this year.
In University Hospital Galway there were 10 surgeries for adults cancelled last week.
In addition, some operations which were due to be carried out on children had to be postponed because of the high volumes of paediatric patients with respiratory illness.
A spokeswoman for the Saolta hospital group, which includes University Hospital Galway, said that as part of pre-planning before Christmas, numbers of elective admissions were significantly less in view of the expected increase in emergencies.
She said that in Sligo University Hospital, as part of the winter plan and having forecast an increase in emergency attendances last week, no routine waiting list patient surgery had been scheduled last week. "However, urgent cases and paediatric cases did go ahead, with the exception of one case."