The National Treatment Purchase Fund says it expects to arrange treatment for 22,000 public patients in private hospitals this year.
This includes 6,000 people waiting to be seen by a consultant at an outpatient clinic.
The scheme, set up in 2002, provides treatment for public patients waiting more than three months for an operation.
The fund's Chief Executive, Pat O'Byrne, said there was no reason any patient should be waiting over three months for a surgical procedure.
The Irish Hospital Consultants Association says that while consultants were co-operating with the scheme, the fund highlighted the lack of capacity in the public hospital system to meet the demands placed upon it.
