A large volume of non-serious complaints to Queensland's child protection service is hampering efforts to help kids most at risk of harm, an inquiry has been told.

Former Communities Department director-general Linda Apelt has told Queensland's child safety inquiry that too many reports of suspected abuse are being referred to the department.

"We are diluting its ability to provide a safety net to those most vulnerable children by asking it to sift and sort a whole range of other concerns that could be better dealt with elsewhere in the system," Ms Apelt said.

She said much time, money and