Around €6m has been overpaid to GPs for deceased medical card holders and for people holding invalid cards.
The figures, released under the Freedom of Information Act, show almost 2,000 doctors received around €2,200 in excess payments due to inaccurate records kept by the General Medical Services scheme.
The Department of Health is asking for the funds to be repaid, but the Irish Medical Organisation is asking for an investigation into payments to doctors before any money is returned.