A separate letter from 60 of the country's top legal and justice organisations has also been sent to the NSW Premier Chris Minns, calling for the new laws to be scrapped.
"This is a devastating betrayal of Aboriginal children and other vulnerable groups across NSW," the letter reads.
"Throwing more children in jail will lead to horrific outcomes for communities, families and those children, compounding abuse and trauma."
Announced last week, the proposed legislation would see a tightening of bail conditions for re-offenders aged 14 to 18 and a new "post and boast" social media offence for crime videos posted online.
The Redfern Legal Centre CEO Camilla Pandolfini told NITV the new laws will not make community safer, despite that being the key driver of the change.
"They will only have a damaging affect on young children we are trying to divert from the criminal justice system," Ms Pandolfini said.
"Evidence shows that place based positive solutions are what divert children from the criminal justice system."
With the laws yet to be passed in parliament, Ms Pandolfini hopes the NSW government will pull the pug before they are enacted.
"We are calling desperately on the NSW government not to purse these laws," she said.
