Advocates have urged Western Australia's Commissioner for Children and Young people to use her authority to investigate the state's crisis-plagued youth justice system.

The call from several prominent youth justice advocates comes after Commissioner Jacqueline McGowan-Jones this week said urgent action, not an inquiry, was needed in WA's crisis-plagued youth justice system.

Speaking to National Indigenous Times on Tuesday, Ms McGowan-Jones pushed for urgent action to address a range of issues in youth justice, but when asked if her office would investigate, she said it was not necessary.

"We already know what is wrong with the youth justice system in WA," she said.

"An inquiry or investigation is unlikely to shed any new light on the major issues."

Ms McGowan-Jones said the review of the Young Offenders Act was an opportunity to implement intervention and diversion measures which addressed the needs of children.

Human rights law expert Hannah McGlade said an inquiry by the Commissioner's office is needed because the state government was still locking children in solitary confinement despite a Supreme Court finding it was unlawful.

"Western Australia has twice the national incarceration rate, and is now incarcerating children in an adult prison," she said.

"One would have thought an inquiry by the Children's Commissioner would have been the obvious response.

"It is very concerning our Commissioner argues against her office exercising its own powers of inquiry on behalf of the most vulnerable children in this state, whose lives are at risk."

Ms McGlade said the Commissioner's office would be better placed to conduct the inquiry than the WA government.

Telethon Kids Institute patron and children's health expert Fiona Stanley said an inquiry by the Commissioner would be important.

Ms Stanley is among advocates urging the creation of a Youth Justice Taskforce involving Aboriginal families to overhaul the youth justice system.

"These children were really damaged before they went into Banksia Hill... and never had a diagnosis," she said.

"If you lock kids up and then use lockdowns because of staff shortages or COVID and don't have a therapeutic program you are going to have kids who get angry, who self-harm and who damage their cells.

"It is such an inhumane way to treat these very damaged children."

Ms Stanley said studies found nearly 90 per cent of the children in Banksia Hill Detention Centre had significant developmental disorders and 35 per cent suffered from Fetal alcohol spectrum disorders.

National Suicide Prevention and Trauma Recovery Project coordinator Megan Krakouer also backed an investigated by the commissioner.

In August questions from MP Brad Pettitt in state parliament revealed there had been 39 self-harm incidents and one attempted suicide in Banksia Hill in a five week period, and 13 self-harm and one attempted suicide in just three weeks at Casuarina's Unit 18.

Ms McGowan-Jones said physical infrastructure deficiencies and staffing shortages at Banksia Hill need to be rectified as a matter of urgency to address the crisis.

"This will not only make Banksia Hill safer for detainees but also allow for Unit 18 to be degazetted as a youth detention facility as soon as possible," she said.

"Psychologists need to be available to young people in detention 24 hours a day, seven days a week... supported in their roles by youth justice officers and detention centre staff who can identify emerging and acute crises and respond appropriately."

Ms McGowan-Jones also renewed her call for the age of criminal responsibility to be raised to 14 years.

She said her team regularly visited Banksia Hill and Unit 18 to speak with the young people detained there.