The Children's Ombudsman has urged political leaders, including the Taoiseach, to push for local authority action on Traveller accommodation.
Dr Niall Muldoon said there is an "opportunity to change things from now onwards".
He told an Oireachtas Committee that there "has to be a statement from the top" to ensure local councillors "step up" and push for Traveller accommodation.
The Joint Committee on Key Issues affecting the Traveller Community today considered the Ombudsman's report; "No End in Site – An investigation into the living conditions of children living on a local authority halting site".
Dr Muldoon said that "under no circumstances" can the appalling living conditions uncovered by the report "be allowed to continue".
He believes that it is "the time to, once and for all, eradicate the racism and discrimination in our local authority planning system".
Dr Muldoon told the committee that "so many other sites have come to light, and nearly every local authority could be held to account in the same manner as this one has".
"It is certainly not an outlier", he added.
The halting site in question cannot be named in order to protect the identities of the children who live there.
Dr Muldoon recounted that 140 people were using toilet and washing facilities designed for 40, and that the overcrowding caused stress and conflict.
A 12-year-old girl had shared how she had watched rats running up and down the walls of their trailer, he said.
Traveller children hear constant "negative abuse, racism, put downs", Dr Muldoon said, adding that they have no safe space to retreat to and recover.
Chairperson of the committee, Independent Senator Eileen Flynn, told her colleagues that she "physically, mentally wasn't able to chair" today's meeting.
Senator Flynn said that reading the Ombudsman's report had brought her "right back to Carrickmines", and her own childhood on a halting site.
"A lot of the children talked about playing in the mud - I was that child", she said. "Not having a safe play to play in."
The Senator noted that the same deprivation confronts "generation after generation" of Travellers.
She has a daughter who is 20 months old, and said she is doing everything she can to "get her past the age of two", which is a fear "every Traveller mother" knows.
Committee members and witnesses applauded her testimony.
"No excuses should be accepted for blocking progress on the provision of Traveller accommodation", Dr Muldoon said.
Politicians are ignoring "very strong and clear" legislation and using veto powers to "block progress", he said.
"Something radical has to happen", he told the committee, as the system has been struck by "paralysis".
Dr Muldoon said that ring-fenced local authority funds for Traveller accommodation "is the only budget that is routinely not spent".
He called for "serious oversight and audit" of the workings of any local authority where such underspends occur.
