Enda Kenny has said he was upset by the findings of a damning review into how state agencies work together when at-risk or troubled youngsters are removed from their families.
The Taoiseach vowed the Government would implement all 17 recommendations in special rapporteur Geoffrey Shannon's report into serious failings into how vulnerable children are cared for outside normal working hours.
"These must and will be followed through," he told the Dáil, when questioned about the planned response.
Work was already "well under way" on many issues raised in the audit while Children's Minister Katherine Zappone is to meet with Justice Minister Frances Fitzgerald about communication between the Garda and State child agency Tusla, he said.
Mr Kenny added: "I'm upset about this."
But Gerry Adams said "expressions of regret just won't cut it any more" and demanded urgent action to fix what he called a broken child protection system.
Child protection training for gardaí was almost non-existent while the lack of co-operation between gardaí and Tusla is "simply breathtaking", the Sinn Féin leader said.
Fianna Fáil leader Micheál Martin said the report was a damning indictment of how Ireland goes about protecting vulnerable children.
The trawl of 5,400 cases from 2008 to 2015 was ordered by the Garda Commissioner Nóirín O'Sullivan following the Children's Ombudsman's inquiry into the removal of two Roma children from their families in 2013 amid unfounded fears the youngsters had been abducted.
Mr Shannon's review found gardaí are inadequately trained to deal with child protection issues.
It said there is poor and limited inter-agency co-ordination between Tusla and gardaí.
It also found some children are repeatedly removed from the same families, social work cover outside of normal working hours is inadequate and there are gaps in protection for children with behavioural problems.