Vulnerable children are still being admitted to "unsuitable" or unsafe adult services, the Mental Health Commission said today.
The number of children admitted to mental health care last year rose by 3.9% last year to 431 - with more than one in five of them housed in adult units.
The Mental Health Commission said it has concerns about safety, isolation and provision of education.
The concerns were raised at the launch of the Commission's annual report - which also notes its "disappointment" that care centres have failed to make significant inroads on compliance.
"Much work remains to be done to change service culture and to refocus on the full delivery of A Vision for Change," said Commission chairman John Saunders.
"Services must be comprehensive, responsive and timely.
"now, more than ever, there is a need to address the systemic issues which prevent the delivery of services and the development of newer more appropriate ones."