Radiologists wrote more than 40 letters to Tallaght Hospital bosses over recent years complaining about a growing backlog in X-rays, the Irish Hospital Consultants Association said.
Hospitals around the Republic of Ireland have been asked to report back on their X-ray procedures after one of the country's largest hospitals admitted 57,000 cases went unchecked.
An investigation has been launched after Tallaght Hospital said two patients - one of whom later died and another who is now undergoing cancer treatment - had their diagnoses delayed as a result of the build-up between 2005 and the end of last year.
Professor Kevin Conlon, chief executive at the south Dublin hospital, said the institution deeply regretted the situation and was working hard to resolve the problem.
"The majority would have been reviewed by a non-radiologist, nevertheless this is totally unacceptable and it arose from systemic and process failures," he said.
"The technology now in place is delivering maximum output as staff work longer hours and through into the weekends to clear this backlog."
But the Irish Hospital Consultants Association (IHCA) insisted the south Dublin hospital has only a third of the number of radiologists needed for a facility its size.
Donal Duffy, assistant general secretary of the IHCA, said it understands all the unchecked X-rays over the past four years were of adults, with no delays in children's cases.
Mr Duffy said although Tallaght was the second busiest of Dublin's teaching hospitals, it had just seven consultant radiologists - far fewer than any of the other teaching hospitals.
"The accepted and recommended standard is that Tallaght should have 18 consultant radiologists for the volume of work it is required to deliver," said Mr Duffy.
The IHCA chief said radiologists had individually and collectively brought the growing delay in reporting X-rays to the attention of hospital bosses over recent years.
"In excess of 40 letters were written to hospital management about this matter by the radiologists," he said.
Mr Duffy said the HSE was responsible for deciding on staffing levels, particularly at consultant level, and receives a monthly update on the activity of each public hospital.
A free helpline has been set up for concerned patients and their families.
© Press Association