Victoria will be the first state to raise the age of criminal responsibility to 12 but the push for further youth justice reform is far from over.
The government has abandoned plans to raise the age to 14 in a policy shift coinciding with a series of high-profile fatalities involving alleged youth offenders.
Fierce debate raged in the state's upper house until almost 2am on Friday over hundreds of amendments to the 1000-page Youth Justice Bill.
The legislation was passed with the support of crossbenchers including the Greens, Legalise Cannabis, Animal Justice Party and Libertarian parties.
The bill is expected to easily pass the lower house.
Other changes include a trial of electronic monitoring of young people on bail, a new charge of committing a serious offence while on bail and certain crimes highlighted in the Bail Act as posing an unacceptable community risk.
The Greens successfully pushed for a ban on spit hoods, which are not used in juvenile facilities, however a teen young than 18 in adult custody was subjected to the practice, the Commission for Children and Young People 2022/23 annual report revealed.
Greens leader Ellen Sandell vowed to continuing to pushing for the age of criminal responsibility to be raised to 14.
"We not give up the fight to continue to reform our justice system so that kids can be safe and we keep kids out of prison," Ms Sandell told reporters in Melbourne on Friday.
"All the evidence shows that sending young kids to prison does not make the community safer."
Opposition spokesman for youth justice and police Brad Battin said laws had been "weakened" and promised to push for more prevention programs and other changes.
"We're effectively giving kids as many get out of jail free cards as they like up until the age of 18," Mr Battin said.
"We're saying to kids that you can commit crimes, whether serious or not, and continue to get diversions, continue to get cautions all the way till you're 18 years old."
Deputy Premier Ben Carroll accused the opposition of walking away from the policy debate and said changes would be incorporated into practices at the state's youth justice facilities.
"It improves community safety, it puts more investment into rehabilitation and finally, it will reduce offending," Mr Carroll said.
"It is important reform - for the first time Victoria now has a stand-alone Youth Justice Act."
Former premier Daniel Andrews intended to lift the age of criminal responsibility to 14 by 2027 with some exceptions.
The recent police shift was welcomed by Victoria's police commissioner but criticised by Indigenous, legal and youth groups.
"International human rights standards and evidence around children's brain development suggest we should raise the age to 14 with no exceptions - and we believe the job is only half done until this is implemented," Jesuit Social Services posted to social media platform X.
Children as young as 10 can be charged and imprisoned across Australia, except in the Northern Territory, which raised the age of criminal responsibility to 12.
The age will be raised to 14 in the ACT by 2025, while the Tasmanian government promised to raise the minimum age of criminal detention to 14.
Public debate on alleged youth offenders flared following the deaths of three men in Melbourne.
William Taylor, 28, and GP Ashley Gordon died following incidents allegedly involving teenagers earlier this year while police are searching for the driver of a car that fatally struck motorcyclist Davide Pollina,19, at the weekend.