The Public Accounts Committee has heard that certain individuals appointed to represent the interests of children in court proceedings were paid "more than the president".
Guardians ad litem are appointed to ensure that the views and wishes of children involved in court proceedings are properly represented.
In some cases separate legal counsel is also appointed.
The PAC has been told that there is currently no national management structure or body charged with oversight of the guardian ad litem service.
The service cost €9.1m in 2014 and €8.2m in both 2015 and 2016.
The committee was told that individuals were paid sums ranging from €40,000 - €240,000 last year.
Fine Gael TD Josepha Madigan said €240,000 is "more than the president of Ireland" earns.
Secretary General of the Department of Children and Youth Affairs Dr Fergal Lynch said payments are made to guardians directly from Tusla, the Child and Family Agency.
He said new legislation is being drafted, to be passed before the end of the year, to reform the system, adding that a programme of fundamental reform would be introduced.
The legislation will provide for the appointment of a single body to oversee the service and will also set fees and provide for clear accountability of the GAL service.
Dr Lynch said the legislation would be in place before the end of the year and a public procurement process would begin to appoint a new body to oversee the service.