The Irish Hospital Consultants Association (IHCA) is hitting out at the government over the latest waiting-list figures.
There are 560,000 people waiting for an outpatient or inpatient appointment.
The IHCA says this is up 9.5% on this time last year and a 61% rise on five years ago.
The association's secretary-general, Martin Varley, says it is down to a recruitment crisis.
"This is an extremely concerning situation for the public," said Mr Varley.
"The association representing consultants is calling on the government to sit down with us and address those problems so we can fill those posts and shorten the waiting lists."
Mr Varley said that the 500 posts are funded and approved.
"But the government has introduced terms and conditions which are effectively driving highly-trained specialists abroad.
"If they were treated equally with their other colleagues they would be more than happy to take up the posts.
"That would have a very quick impact in terms of more timely care for patients."