Almost 215,000 children are on waiting lists for health care services, with more than one in four waiting for longer than a year.
Figures seen by RTÉ News give a comprehensive picture of how long children are waiting for a wide range of health services.
They show big variations depending on where the children live.
There are 90,000 children waiting for community health care services, many of which are used by children with disabilities for whom early intervention is crucial.
This includes 19,000 children waiting for speech and language therapy.
The figures show that 2,000 of these have been waiting for longer than a year and 300 more than two years.
Waiting lists in north Dublin are the highest in the country, with 2,400 children in the queue.
This compares to just ten children on a waiting list for speech and language therapy in Dún Laoghaire and zero for Dublin South East.
There are more than 7,000 children and teenagers waiting to see a psychologist, jumping by almost a fifth in the past year.
Added to the 117,000 children on hospital waiting lists, it brings the total figure of children waiting for public health care to 215,000.
Fianna Fáil's spokesperson on health Stephen Donnelly, who got the figures in response to a series of parliamentary questions, said they were shocking and a dark stain on the country.
Speaking on RTÉ's Morning Ireland, Mr Donnelly described it as an "appalling situation".
He said parents are getting letters from overwhelmed service providers where they cannot tell them when their children will be seen.
"More and more parents have been coming to me who are waiting for over a year for surgery.
Parents who are coming to me with children with special needs and who desperately need supports."
The HSE said it was fully committed to tackling long waiting times and there had been a 27% in its general paediatric outpatient waiting list in the past year.
The children's charity, Barnardos, has said there is "blatant inequality" in relation to how children access vital health services across the country.
The organisation said it is very concerned with the number of children on waiting lists for health care services.
The charity's Chief Executive Suzanne Connolly, said Barnardos is particularly concerned about the "lottery" based on where children live.
"In some areas there is a very low to no waiting lists, and some areas it is very high. We think that is evidence of blatant inequality in Irish society," she told RTÉ News.
The figures show that, for example, in north Dublin there are 1,469 children on waiting lists for follow-up speech and language therapy compared to zero for Dublin south east and ten for Dún Laoghaire.
Ms Connolly said some parents can afford to buy the services for their child privately and some cannot.
"What we would say to the HSE is to prioritise the services in the areas where, they know, because of socio-economic contexts, parents cannot afford it. Their children should be entitled to get the treatment they need as well."
She said the sooner a child with special needs gets specialist intervention therapies, the better they are able to learn and develop.
"If you have a waiting list, that means a child may be further back than they need to be in terms of their developmental trajectory," she said.