A review has found flaws in the complaints system used by Queensland’s child safety department.

A recent submission by the Queensland Ombudsman says the way the Department of Child Safety, Youth and Women handles complaints about children's safety goes against legislation.

Ombudsman Phil Clarke said his review found several issues including misclassification and under-reporting.

Possibly the most disturbing revelation is that the department's Complaint Management System does not comply with the law.

“The internal review mechanism provided under the department's complaints management policy and procedure does not accord with the Australian/New Zealand Standard because it does not provide for a merits review of a previous complaint process or decision,” the report states.

This means the system does not comply with the industry standard, as required by law.

The report found the complaint system to be “unnecessarily complex and confusing”, creating “frustration and delay”.

“Decision-making in the management of complaints was a key concern identified in the investigation,” the report says.

“A lack of clarity about how a decision about a complaint should be made and who should be the decision-maker has resulted in poor outcomes for complainants.”

The report makes nine recommendations, including one to ensure the system meets the Australian standard, by restructuring the internal review process.

There are over 11,400 youths in the state's child protection system.