The only hospital in the State offering combined kidney and pancreatic transplants has had to suspend the service because the consultant who provided it is on sick leave.
Beaumont hospital in Dublin said it carried out three such transplants last year but was not now in a position to offer the transplants "due to circumstances beyond its control".
The operations were performed by transplant surgeon David Hickey who has been on sick leave for a number of months. It is not clear when he will be able to return to work.
The hospital said it would be almost impossible to find a locum consultant who would have the skills to carry out combined kidney and pancreatic transplants. However, it does still have staff capable of performing kidney transplants on their own.
"There are just under 20 patients awaiting a combined transplant and these remain on the waiting list for kidney transplants when suitable donated organs become available. The hospital would then expect to offer pancreas-after-kidney transplants, where appropriate, at a later stage," the hospital said in a statement. "The preferred option is to offer a combined transplant to those for whom it is appropriate . . . however, for the vast majority of patients with kidney failure due to diabetes, the first priority is a kidney transplant.
"This offers a considerable survival advantage and improvement in quality of life over remaining on dialysis."
The suspension of the combined kidney and pancreatic transplant service came to light after Marion Blair from Blanchardstown, Dublin, who is waiting for a combined kidney and pancreatic transplant, spoke out about having discovered by accident that Mr Hickey was on leave and that her surgery could therefore not take place.
She has already been waiting a number of years for her transplant. Her kidneys failed nearly five years ago as a result of diabetes.
The hospital statement said it was "sorry if any patient learned of the suspense of this service in advance of being formally told of it by the hospital".
Mark Murphy, the chief executive of the Irish Kidney Association, said the issue was of concern. He added that the pancreatic transplant programme had never been "funded properly by the State at all".