Over 16,000 adults and children are waiting more than three months for surgery in Ireland.
A new report from the National Treatment Purchase Fund (NTPF) shows another 5,300 patients are also waiting over three months for treatment for medical conditions.
The fund has identified five hospitals which it says account for over half of the 2,155 patients waiting longer than a year for surgery.
The hospitals are: Letterkenny General, Sligo General, Midland Regional in Tullamore, Cork University and Tallaght hospital in Dublin.
The Minister for Health, Mary Harney, has said it is inexcusable that more than 2,000 patients are waiting longer than a year for surgery.
Ensuring referrals to the NTPF for those waiting longest for treatment is 'a top priority', Minister Harney said.
'I have asked the NTPF and the HSE to work together to tackle this issue and to report back to me regularly on their progress.
'It is deeply unfair to patients who have been waiting for operations not to refer them.
'To refer them to the NTPF gives patients themselves the option for treatment. The money and the resources are there. The quality is assured.
'98 to 99% of patients surveyed who have used the NTPF have been satisfied.
'It is now imperative that any hospital with patients waiting longer than 12 months for their operation refers them to the NTPF immediately. Many other hospitals do this routinely.
'We have seen good progress in particular since the beginning of the year on getting treatment for those waiting longest. Patients of every hospital deserve the same,' said the Minister.
NTPF chief executive Pat O'Byrne said: 'We will work with the HSE and the hospitals to address this entirely unacceptable situation.
'The renewed focus on non referring hospitals will build constructively on progress already made to see that the longest waiters benefit from treatment as soon as possible.'
The Government's 2001 National Health Strategy promised that by the end of 2004, no public patient would wait longer than three months for treatment.
Since its establishment in 2002, the NTPF has arranged private treatment for over 100,000 public patients who were waiting longer than three months for surgery.
It says that average waiting times for the most common surgical procedures are now two to five months.
The NTPF plans to organise 23,500 operations and outpatient clinics for 13,500 patients this year.
Most of the treatments are provided in private hospitals and less than 1% of patients are referred abroad.
