The chairperson of a local Down Syndrome centre says waiting times for disability assessments leads to children "missing out on vital time they can never get back".
The average time parents are awaiting an initial assessment for their children is 17 months, despite a legal requirement for this to be completed within six months.
Disabilities Minister Anne Rabbitte has expressed her "sincere apologies to any family experiencing such delays".
Martin McBreen says such waiting times led to the establishment of the Down Syndrome Centre North East in 2017.
He says it's "a huge problem that has been going on for so long, adding that these things "can't be put off":