The Queensland government on Tuesday confirmed it would introduce the legislation to parliament this week, creating a new offence that would apply to both juveniles and adult offenders.
The measures are an extension of the state's "adult crime, adult time" laws that allow for youth offenders to face a mandatory life sentence for serious offences such as murder.
Under the new legislation, anyone who commits any of the 47 "adult crime, adult time" offences while on bail will receive a minimum mandatory sentence of 12 months.
"They will be the most significant bail reforms this state has ever seen - they will be the strongest bail reforms in the nation," Queensland Premier David Crisafulli told parliament on Tuesday.
However, the reforms have sparked fears for the state's overextended youth detention system, with overcrowding already a concern.
Youth detention staff returned to work on Tuesday following a 24-hour strike amid talks with the state government over safer working conditions.
Youth Advocacy Centre chief executive Katherine Hayes told AAP she was concerned the new reforms would create more problems.
"All of the detention centres in Queensland ... are operating beyond their safe capacity, so they're all bursting at the seams," she said.
She said this created an overflow into watchhouses around the state, with 57 kids currently waiting for a place in a detention centre.
Ms Hayes said Queensland already had the country's toughest youth bail laws before the latest reform.
"Why people should be concerned about that is because it means that children aren't being rehabilitated while they're in detention," she said.
"Every day in the detention centres and watchhouses, children's human rights are being breached and the consequence of that is they continue to be damaged and traumatised, and will continue to offend."
Queensland locks up the most children in the country, with about 300 in detention on an average night, according to a 2025 Australian Institute of Health and Welfare report.
"There are more than NSW and Victoria combined," Ms Hayes said of the Queensland total.
"Yet we've got a high reoffending rate, so we're just doubling down on following a strategy that doesn't reduce offending."
Queensland's adult prison system has also come under fire after a damning recent report found almost half of the state's inmates released from custody returned to jail within two years.
Inmate numbers had surged 54 per cent in a decade to 11,278, the state's auditor-general report said.
