The Health Service Executive has blamed a combination of human error and procedural gaps for a payment of €1 million being made by mistake to a health worker.
The HSE said that the error in a new computerised payment system occurred over a year ago.
It said measures were in place to ensure the problem did not occur again and said that the system was now working well.
It was earlier reported that the payment was spotted by the recipient and was not identified by the payroll computer system which cost €120m to install.
In advance of the HSE's statement, Tánaiste and Health Minister Mary Harney acknowledged that there were serious concerns about the system, while Fine Gael accused the Government of incompetence.
The party's Spokesman on Finance, Richard Bruton, said the possibility that €120m had been wasted on an ineffective IT project raised serious issues about the competency of the Government to spend taxpayers' money effectively.
In response to a question yesterday at the Oireachtas Health Committee, Ms Harney acknowledged that there were serious concerns about the department's computer system.
The computer system in question - Personnel, Payroll and Related Systems - has been the subject of an investigation by the taxpayers' watchdog, the Comptroller and Auditor General, John Purcell.
The investigation found that the system had 'fundamental errors' and that only four people know how it is supposed to work.
