Revealed: Social worker was paid €307,000 in one year
The guardians are paid €125 an hour
Five social workers were each paid more than €370,000 to represent children in court - with one earning €307,000 in a single year.
Guardians ad litem are appointed by a judge to protect the best interests of children who have been taken into the State's care.
It is understood there are currently about 65 designated guardians ad litem, often called 'GALs', operating in the State.
Tusla, the Child and Family Agency, spent €15.2m on GAL services in 2016.
They are paid €125 an hour - but there is currently no national management structure or body charged with oversight of the service.
The rate covers time spent attending court, writing court reports, meeting with the child, interviewing those relevant to its circumstances and observing the child's interaction with them.
It also includes dealing with all relevant correspondence relating to a particular case.
While the majority of GALs have a social work background, there is no requirement for any particular qualification.
Now, new records obtained by the Sunday Independent reveal massive sums being made by a select group of specialists operating in this area.
Twelve individuals and agencies acting as guardians to children in childcare court proceedings each received more than €100,000 from Tusla last year.
Two GALs both shared a payment pot of €304,036 in 2016. Records show they earned €486,489 and €403,509 respectively in the past three years for their work representing the interests of children in court proceedings.
Another GAL earned €307,465 in 2015.
In total, that individual has received payments of €528,942 from Tusla since 2014.
Records show five social workers have each received more than €370,000 since 2014 to represent children in court.
Barnardos is the largest and longest-established national guardian ad litem service in Ireland, having received more than €10m in GAL payments since 2014.
In 2016, the children's charity was paid €3.1m, while in 2015 it received €3.8m.
In 2014, the figure stood at €3m.
Last year, it contracted the services of 32 freelance self-employed contractors to provide a service to 840 children.
In a statement, it stressed it has long called for the need for a "properly regulated and managed system".
It believes a single agency is required that will be accountable for the management and supervision of all GALs, which can provide "real value for money", while ensuring that children have a voice "where and when they need it most".
Speaking last month at the Public Accounts Committee, Department of Children secretary general Dr Fergal Lynch said the system was in need of "significant reform".
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 restructuring 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.
In a statement, the department said the overall objective of this reform is to extend the system to benefit the "greatest number of children and young people, and to provide a service that is high quality and sustainable into the future."
Meanwhile, Tusla said it welcomes the proposed restructuring of the system to provide an "effective nationally managed and delivered" service.
"As there is currently no governing body assigned with the responsibility to monitor or supervise the work performed by guardians ad litem, Tusla cannot verify the accuracy of the hours invoiced.
"Since 2015, Tusla has developed and applied additional control checks to ensure consistency in invoices received from guardians ad litem and identify any anomalies," it added.