More than 17,000 public patients awaiting outpatient appointments with hospital consultants, in some instances for up to five years, were offered their appointments in private hospitals last year.
However only 7,480 of these patients or 42 per cent of all those contacted accepted the offer.
And subsequently 10 per cent of the 7,480 patients who accepted an offer of treatment did not turn up when called for their appointment on two occasions.
The offers were made to them through the National Treatment Purchase Fund (NTPF), which began to tackle outpatient waiting lists on a pilot basis in 2005.
A report published yesterday said that nearly 2,000 (11 per cent) of the 17,000-plus patients contacted last year declined the offer of treatment in the private sector for a number of reasons.
"These included unwillingness to go to to another hospital or patients wishing to stay with their original hospital," it said.
A further 4,343 patients (24 per cent) did not respond to the offer and are being contacted again while 4,000 patients (23 per cent) were found to no longer want or need an outpatient appointment.
Most of the patients referred to the private sector were referred to ear, nose and throat or orthopaedic specialists.
The west was the region which saw most patients removed from outpatient waiting lists as a result of the initiative.
The NTPF said that as a result of the programme waiting times for a first outpatient appointment with an orthopaedic consultant at Cork University Hospital have been reduced from five years to 18 months.
At the Mater hospital in Dublin, it said, waiting times for a first outpatient appointment with an ENT specialist had been reduced from four years to four months.
The average cost per patient of referring them to the private sector for their outpatient appointments was €395.
It is not known how many patients are on outpatient waiting lists at hospitals across the State as traditionally only inpatient waiting list data has been collated centrally.
However anecdotal evidence has suggested that some patients on outpatient waiting lists have been on them for years.
The NTPF has been attempting to target the longest outpatient waiting lists with its pilot programme, which began in 2005.
Since then, it says 19,000 patients have either received outpatient appointments in the private sector or they have been taken off the waiting lists because they no longer require an appointment.
It hopes to arrange a further 9,500 outpatient appointments for public patients in the private sector this year.
Patients can contact the National Treatment Purchase Fund directly on 1890 720 820 to discuss their treatment options.