Two-thirds of children who are charged with committing a crime and denied bail in Victoria aren't ultimately sentenced to detention, a landmark report has found.
The daily average number of children held on remand has increased from 42 in 2014 to 90 last year.
The Sentencing Advisory Council report, released on Tuesday, also found Aboriginal and Torres Strait Islander children are significantly over-represented in the figures.
"Being remanded separates a child from family and community, disrupts education and ultimately increases a child's risk of future offending," council deputy chair Lisa Ward said.
The research suggests a significant number of children might be remanded because they couldn't access supports.
"Many remand decisions are made outside of business hours when access to support services is limited," Ms Ward said.
In 2017-18, 442 children spent at least one day on remand, with 66 per cent not given a custodial sentence.
It cost $15 million to hold the children who didn't receive a custodial sentence on remand, the report determined.
Aboriginal and Torres Strait Islander children made up 15 per cent of those held on remand - the process of holding someone accused of committing a crime in custody while their legal matters are finalised.
"This is the first study in Australia to examine what happens at the end of cases in which children have been held on remand," Ms Ward said.
The council has called for the establishment of a Victoria-wide 24-hour bail system specifically for children.
It also wants the Children's Court expanded to other locations and specialist services and programs for Indigenous children.
