It has emerged that the body in charge of maintaining national statistics paid someone nearly €300,000 in wages - even though that person did not work there any more.
The official report from the Comptroller and Auditor General reveals that the CSO only stopped paying the person's wages in November 2011, even though the person had not worked there since 2006.
The member of staff wrote to the CSO in 2007 to tell them about the error, but the payments continued for another four years.
The worker was overpaid by €296,000, but has voluntarily returned the money.