There are calls for the HSE to appear before the Oireachtas Children's Committee to explain why thousands of children with disabilities are still waiting a year for a needs assessment.
Latest figures show 4,000 are currently on the waiting list.
The Ombudsman for Children says he's extremely concerned the number has shot back up despite improvements earlier this year.
Niall Muldoon says the HSE needs to account fully and publicly for the ongoing problems and outline what's being done to address the backlog.
"One recent complaint we received on this issue was made on behalf of Callum, who is six and has been awaiting a HSE multidisciplinary assessment for four years - since he was 28 months old."
"There are too many children like Callum who are waiting far too long for an assessment. The same children will have to wait again for the services they need."
Dr Muldoon says children must be assessed with urgency, which he says is their right under the Disability Act 2005.
