The Northern Territory Children's Commissioner says she was never briefed on new laws allowing public transport officers to use pepper spray on children.
The measures came into effect on Tuesday, allowing Transit Safety Officers operating on Darwin buses and interchanges, to use the spray against commuters of any age if confronted with violent behaviour.
However, the office of the Children's Commissioner said it was not consulted on the move, despite under 18-year-olds being frequent bus users.
"Children and young people who find themselves in contact with authorities such as TSOs are often vulnerable and have experienced trauma," Commissioner Nicole Hucks said in a statement.
"This should not be exacerbated by exposing them to more harm."
Ms Hucks said she was concerned about the training provided and the level of oversight over the TSOs.
"I have concerns about the operational policy environment in which TSOs are able to utilise these weapons...together with the accountability systems and oversight when the weapon is utilised," she said.
The territory is the third jurisdiction to require the officers to carry the devices, bringing it into line with Victoria and Western Australia.
NT Chief Minister Natasha Fyles said the "last-resort" devices were not designed for use on young people though TSOs could find it difficult to identify someone's age.
"As you have older children in a heated situation, they'll make a decision based on the safety, not necessarily trying to identify the age," she said on ABC radio.
"Some children look older than they are, some adults look younger than they are."
NT Police Commissioner Michael Murphy said the general public needed to be protected from children as well as adults.
"Young people do present with risk as well, they do carry weapons, and they do threaten members of the public," he said.
"The actions of police and other government officials are under scrutiny from the Ombudsman's Office."
Police powers have also increased in recent weeks after new wanding laws came into effect in September allowing police to randomly search people for weapons in "high-risk" areas of the NT.
The only person who has been arrested and charged with a weapons offence under the new laws was a man carrying an axe in Alice Springs.
The new laws form part of the territory government's suite of changes targeting crime which were introduced after the death of Darwin bottle-shop worker Declan Laverty in March.