A District Court judge has found police in Broken Hill were wrong to strip search a 17-year-old intellectually disabled boy by the side of the road.

A magistrate found the boy, who cannot be named because of his age, guilty of possessing a small amount of cannabis after he was arrested and strip-searched in July 2011.

But his lawyers appealed against that, arguing the evidence was not admissible because the strip search was improper.

Judge Jennifer English agreed.

She found police had no reasonable grounds for arresting the boy and searching in his underpants.

Stephen Lawrence from the Aboriginal Legal Service, which represents the boy, says there was no valid reason to stop the boy.

"The young person was walking down the street in Broken Hill at about 5:30 in the afternoon, wasn't doing anything untoward or anything like that," he said.

"He was stopped and searched by police unlawfully, because the police simply had no reasonable suspicion.

"So this is a case of a young person simply being stopped for no reason. For no valid reason."

Mr Lawrence says the boy had been stopped by police 26 times in the previous two-and-a-half years and he had never once been found with drugs.

He says there should be an investigation.

"Any citizen in the community would find that to be an unusual circumstance and certainly one that would call for an investigation," he said.

Mr Lawrence says the boy's family has requested the state ombudsman launch an inquiry into the case.

A police spokesman says it is reviewing the court's decision to see whether any action will be taken.