The children's minister has blamed the shortage of room in detention centres on a threefold increase in the number of young offenders.
Frances Fitzgerald's office came under fire from a judge who warned child criminals are being freed to reoffend because there are no beds available.
The minister said a Government decision to stop sending 16-year-olds to adult prisons, and a spike in judges remanding teenagers, has led to three times as many being detained in recent years.
Judge Ann Ryan had criticised the lack of provision for teenagers as she called two senior officials from the Department of Youth and Children into the Children's Court in Dublin to answer questions. She told Michelle Shannon and Tony O'Donovan that a decision to send a youth into detention was a last resort for the court.
"In recent weeks we found ourselves in the position where there are no beds, letting a child who should be in detention free into the community to perhaps commit some awful crime," she said. "Where do we stand? I don't think it's good enough you can say we're having audits and committee meetings."
The judge was told an eight-bed unit was ready to open, but delays due to staffing issues on new rosters were being audited.
Ms Fitzgerald also said an unusual peak in juvenile crime, or a vote of confidence by the judiciary in the Oberstown facility, had resulted in the threefold increase in 16-year-old detainees since 2011.
The children's minister also called on the 203 staff working in Trinity House, Oberstown Boys and Oberstown Girls - all in Lusk, Co Dublin - to co-operate with the new arrangements for the opening of a new eight-bed wing on the campus.
"For the first time under this Government we do not have 16-year-olds being sent to adult prisons," she said. "For decades, this state locked 16-year-old boys in adult prisons - we have stopped that.
"This Government has grasped the challenge of ensuring that proper facilities will be available in a suitable setting by committing 50 million euro to the development of a new campus at Oberstown."