He said he was also concerned at the number of children aged 16 and 17 sent to juvenile and adult prisons.
He wanted to see all child offenders, except for the most serious offenders, cared for in child detention schools.
His comments follow reports yesterday that 147 young people aged between 15 and 17 have been placed in youth and adult prisons since January this year.
The bulk have been placed in St Patrick’s Institution for Young Offenders, which caters for those aged between 16 and 21, with a smaller number at Cloverhill and Limerick prisons.
Mr Lenihan was speaking at the launch of the 2004 annual report of the Special Residential Services Board (SRSB), which highlighted concerns over both issues.
“I attach a lot of importance to independent inspection of child detention schools,” said Mr Lenihan.
“I’m anxious that the remit of the Social Services Inspectorate should be extended to the justice facilities. That’s one definite area I want to bring forward proposals on.”
He said the Social Services Inspectorate (SSI) already had powers to inspect child residential centres. He said he would consider proposals by the Ombudsman for Children, Emily Logan, that her investigation powers be extended to adult prisons where children were held.
Mr Lenihan said he would bring proposals soon to the Government on these and other issues.
He said these issues were being examined by a team in the Department of Justice which had been set up to look at the entire youth justice system.
The placement of children in adult places of detention is in contravention of the UN Convention on the Rights of the Child and the European Convention on Human Rights.
SRSB chief executive Roger Killeen welcomed the minister’s commitment to address the concerns raised in the report.
Mr Killeen also raised concerns that a section of the Children Act - which gives district courts the power to order the detention of a child to a special care unit - had still not been implemented.
He said an expert review panel had been set up and trained for over a year waiting for this to happen.