It's an increase of 31% since February, before the Covid-19 pandemic began.
The new figures relate to the four Children's Health Ireland hospitals in Dublin.
Dr Martin Daly, a former president of the Irish Medical Organisation, says the coronavirus crisis has worsened the situation.
"It has made an already bad situation worse, and it has been a major concern that COVID would displace non-COVID care from the hospital and would increase the length of waiting lists, however those waiting lists existed prior to COVID, and we had a real capacity issue at the outset of COVID in terms of Children Services."
