The NSW coalition on Sunday pledged to make young offenders face tougher penalties within 100 days of winning government if it triumphs at the March state election.
The opposition said it would expand the list of serious indictable offences, meaning adult sentences could apply for juveniles who committed a greater range of crimes.
The state Labor government recently announced a suite of reforms that could see children suspected of organising crime-linked public shootings or firebombings to be placed on trial as adults and face tougher penalties.
The measure followed a series of gangland killings, including several involving cases of mistaken identity and crimes allegedly involving underage guns-for-hire.
But the opposition said the government had not gone hard enough and tougher penalties were required, including for people who recruited children to commit offences, accusing Labor of losing control of crime.
"But if you commit a serious adult crime, there should be serious adult consequences," Opposition leader Kellie Sloane said.
Guideline sentencing and new sentencing principles would be created to ensure detention was not treated as a last resort and greater weight was given to victim impact rather than the age of the offender.
"If you've got kids who are being recruited to steal cars that then become kill cars for assassinations, if you've got kids who think it's a great idea to go on the criminal's version of Airtasker and bid for abductions," acting shadow attorney-general Susan Carter said.
"We need to be actually expanding our idea of what these serious crimes are and showing that there are real consequences."
The proposed laws would be accompanied by further investment in youth diversion, with school suspension and post-detention rehabilitation programs expanded, and a doubling of funding to the Community Safety Investment Fund.
But Greens MP Sue Higginson said both the government and opposition approaches ignored the root issues driving young people to commit crimes, including ongoing inequality and cost-of-living issues.
"We know that these young people-they are preyed upon, they're coerced," she told AAP.
"Any politician right now worth their weight in salt, who has the power, wants to see these young people that commit these awful crimes genuinely rehabilitated.Â
"You do that through the juvenile justice system, not train them to be better criminals through the adult prison system."
Deputy Premier Prue Car said her government's proposed crime crackdown already went far enough and urged the opposition to back the measures.
"We urge the Liberals and the Nationals to support this legislation if they are actually fair dinkum about keeping the people of NSW safe," she said.
