The Central Remedial Clinic has confirmed that money donated by the public is being used to top up salaries of some its staff.
In a statement, it said the funds were raised by a separate company called the Friends and Supporters of the Remedial Clinic.
It admitted the additional salary amounts were over the Department of Health's consolidated pay scales.
It said the money contained in the fund is generated from a share of the operation of a lottery.
Labour TD for Dublin Mid West, Robert Dowds, said the reputation and fundraising capacity of the CRC would be damaged if it doesn't immediately address the issue of funding and top up payments to staff.
On RTÉ's Six One News, Mr Dowds said he would ask the CRC to come before the Public Accounts Committee and to end any topping up of salaries without delay.
He also said more information needed to be provided in relation to the source and use of the almost €14m fund held by Friends and Supporters of the Remedial Clinic.