The probe into Queensland's child safety system - the third of its kind since 2003 - held its final hearing on Thursday, before Commissioner Paul Anastassiou KC hands his report to the government on Friday.
Mr Anastassiou said he hoped the inquiry's outcomes could help focus government policy and action on the causes of harm to children.
"They are alcohol abuse, drug abuse, domestic violence, and mental health issues," he said.
"They are villains who, in concert, are nearly always present when a child is removed into the care of the state."
The inquiry had given a platform to the voices of children "so their stories may be heard by those in a position to … fix the child protection system that is fundamentally broken", he said.
Counsel Assisting Robyn Sweet KC said the inquiry, which began in July 2025, was not established because of a single tragedy or failure.
"The questions about the failures and accountability of the child safety system have become too numerous, too serious, and too interconnected to be answered in a piecemeal way by … the system," she said.
The commission has chronicled "rapacious" growth in spending, and substantial growth in children in out-of-home care and the residential care sector, and the intersection between the child safety and justice systems.
The number of children in out-of-home care increased from 7999 in 2011/12 to 10,092 in 2023/24, while the number in residential care rose from 653 to 1994 over the same period.
Spending on child safety services increased from $753 million to $2.36 billion in that time.
The cost of residential care has surged to $500,000 per child annually, with $500 million in state funds funnelled to 125 unlicensed providers in the 2024/25 financial year.
"Those figures demonstrate a system under sustained pressure with major consequences for children, families, carers, government and the community," Ms Sweet said.
Data also showed 72.9 per cent of children under youth justice supervision in 2022/23 had interacted with the child safety system in the preceding 10 years.
"The relationship between care, risk, instability, and offending requires serious examination by this commission," Ms Sweet said.
The child safety system needed to be scrutinised on a systemic level, she said.
"It must be examined not only by asking what happens to children once they enter care, but by asking how decisions are made before they enter care, and at each point throughout the care journeys of the children," she said.
The commission held 49 hearings and received 1193 submissions.
On Thursday, the commission also released submissions from children and young people, carers, and frontline workers.
Mr Anastassiou said the "powerful" submissions highlighted "Queensland's child protection system has not been working as it should".
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