The Health Service Executive says some top-up payments for senior staff in hospitals and health agencies have been in place since 1996.
A number of senior HSE executives are appearing before the Oireachtas Public Accounts Committee to face questions about the unsanctioned payments.
The HSE says that so far it deems that only seven of the 42 hospitals and health agencies are fully in compliance with public sector pay levels.
The HSE says some of the facilities say they got a verbal approval for the payments, but the Department of Public Expenditure and Reform says there is no paper trail.
Tony O'Brien is the Director General of the HSE:
