An organisation has started a petition calling for the Oranga Tamariki (Responding to Serious Youth Offending) Amendment Bill to be withdrawn.
Save the Children New Zealand launched the 'Boot the Bill' campaign on Friday.
Jacqui Southey, child advocacy and research director, told RNZ the bill, currently before the Social Services and Community Select Committee, would reintroduce "harmful" military-style academies and permit the use of physical force against children.
"We want New Zealanders to know about it and to know what it means, and we're giving them the opportunity to have their say through this campaign."
Southey said it was an "outdated methodology".
"[It] has been tried before in New Zealand, with little to no effect in preventing youth offending."
"The evidence is clear, both internationally and here in New Zealand, that this style of youth justice response simply does not work.
"It does not make New Zealand safer. It does not stop reoffending. It does not help young people in conflict with the law move towards a better future.
"And furthermore, it seriously breaches their rights. Children's rights need to be upheld, whether they're in conflict with the law or not."
Southey said the testimonies of survivors, as part of the Royal Commission of Inquiry into Abuse in Care, had proved that children were violently abused and traumatised in state-funded, boot camp-style institutions in New Zealand.
It had happened as recently as 2004, Southey added, at the Te Whakapakari Youth Programme.
"While it claimed to promote drug abuse rehabilitation, self-esteem and skills development, Māoritanga and confidence building, underpinned by military-style discipline, instead, children suffered cruel, violent, and inhumane treatment, including extreme psychological, physical and sexual abuse.
"A former minister of Child, Youth and Family, Ruth Dyson, was quoted as saying, 'A lot of government money was put into that programme and in the end it resulted in the state funding violence and abuse towards children and young people.'"
Southey said most young offenders were victims themselves, having experienced high rates of criminal abuse, neglect, and violence.
"If New Zealand is to be truly effective in preventing youth crime, we need to be serious about preventing harm to children occurring in the first place.
"That means investing in programmes and policies to strengthen families, particularly those struggling, to ensure good outcomes for children in both the short and long term."
During the first reading in November, Minister for Children Karen Chhour said she believed the bill was the last chance to prevent young offenders from entering the adult jurisdiction and becoming persistent adult offenders.
"I want to do everything we can to break that cycle of offending."
On Friday, Chhour told RNZ she encouraged people to engage in the select committee process to give their feedback on the bill.
"The right to campaign, protest, and petition is a blessing we have.
"I fully welcome and encourage New Zealanders to do so on their beliefs and causes, provided it is safe and legal."
Sign up for Ngā Pitopito Kōrero, a daily newsletter curated by our editors and delivered straight to your inbox every weekday.