A Monaghan Down Syndrome Centre says waiting times for disability assessments leads to children "missing out on vital time they can never get back".
It comes as nearly 4,000 children nationally are currently waiting for an Assessment of Need.
The Ombudsman for Children, Dr Niall Muldoon, has called for the HSE to appear before the Oireachtas to account fully and publicly for the ongoing problems with Assessment of Need, despite significant commitments made to address these problems.
He said an explanation is needed from the HSE for the build-up in cases again, and that they must outline what is being done to address it.
Meanwhile, lengthy waiting times for assessment led to the establishment of the Down Syndrome Centre North East in 2017.
Martin McBreen from the Carrickmacross-based centre says it's 'a huge problem that has been going on for so long' and the time has now come to stop putting assessments off.