The HSE was sued over 200 times in the space of three years in relation to needs assessments for children with disabilities.
Latest figures show over 3,600 assessments are overdue completion.
An 'assessment of need' allows a child to be diagnosed with a disability and then apply for the care they need.
Fiona Ferris, deputy chief executive of autism charity As I Am, told Newstalk: "An assessment of exactly what level of need that child may have, if any, is something that can be applied for by a parent or by a legal guardian, and it does actually hold a legal timeframe as well. Once an assessment of need has been applied for the assessment needs to have begun within three months and completed in another three months."
Latest figures show 3,609 assessments are overdue. New freedom of information figures show 212 legal actions were taken against the HSE between 2018 and 2020 in relation to these assessments.
The HSE's legal costs in these cases were nearly €701,000.
Ms Ferris says it's very disappointing parents have to go down this route.
"If you have a child who is autistic or if you have a child who is displaying any kind of additional needs above and beyond their peers, everything is a fight, this is just another fight they have to go through."
Minister for Disabilities Anne Rabbitte recently promised to clear the waiting lists for assessments of need within the next year.