A senior Aboriginal Legal Service of WA director has called for a royal commission into youth justice and child protection and for the sacking of Corrective Services Minister Bill Johnston.

ALSWA legal servies director Peter Collins made the call after Justice Paul Tottle ruled on Thursday that confining a 14-year-old boy in a cell for more than 20 hours on 26 occasions was unlawful.

ALSWA applied for a judicial review of the lockdowns on June 23, having raised concerns over the legality of the conditions with Mr Johnston and the Department of Justice.

Mr Collins said the conditions in Banksia Hill juvenile detention centre were "scandalous".

"(It is) an indictment on the government for a Supreme Court justice to have found that it has acted unlawfully - and for a young person in its care to have been be treated in this way," he said.

"But it goes further than that - this is another chapter in the long history of the appalling treatment of Aboriginal people in custody.

"The punishment involved in being in Banksia Hill should be confined to the loss of liberty - not being locked up for days on end in barbaric conditions."

Mr Collins said change was urgently needed and that the current approach would create more crime.

"The minister Bill Johnston has stood by for months on end and done nothing about the lockdowns, save for sending vulnerable children to a maximum security jail," he said.

"He should be stripped of this portfolio and it should be given to someone who is prepared to act in accordance with the law.

"There needs to be a royal commission into youth justice and the care and protection systems, because so many children cycle through the protection system only to land in Banksia Hill."

Mr Collins said Aboriginal communities needed resources to design and lead strategies and to deal with juvenile crime.

Mr Johnston said he had always acknowledged this was difficult period for Banksia Hill detainees

"This is why on 5 July, 2022 I announced the gazetting of a new secondary youth detention facility to ensure the continued safety of staff and detainees," he said.

"Seventeen of the most difficult cohort of young people with complex needs were moved from Banksia Hill to Unit 18 (at Casuarina adult prison) on the 20 July 2022."

Mr Johnston said Unit 18 had provided an opportunity "to address the challenges of this group of young people".

He said there had been a significant reduction of incidents at Banksia Hill since the move.

"Banksia Hill continues to see improvements in staffing levels since 38 new probationary officers commenced in April and May 2022," Mr Johnston said.

"A further 10 probationary officers commenced their three-week orientation on 15 August 2022 and will commence their rostered duties on completion."

Mr Johnston said there were nine detainees still at Unit 18 who may return to Banksia Hill when suitable.

National Indigenous Times has contacted WA Attorney General John Quigley for comment on the call for a Royal Commission.