The youth justice system in Western Australia needs an urgent "trauma-informed intervention", Inspector of Custodial Services Eamon Ryan wrote in his office's annual report on Tuesday.

The Annual Report tabled in parliament had a strong focus on what it called "the crisis in youth detention".

"The cycle cannot continue and something needs to change, I believe that a welfare focused and trauma-informed intervention is urgently required," Mr Ryan wrote.

The report provided a history of its inspections and reports of Bankisa Hill dating back to 2005 and noted the "striking similarities" in the issues identified again and again.

"This extensive body of work has identified a number of key themes, including: the need for a trauma informed operational philosophy; issues around behaviour management and out of cell hours; and workforce trauma and centre target hardening.

"What is remarkable is that short periods of progress and improvement have always been followed by crisis and instability," Mr Ryan wrote.

"Of significant concern is that the situation deteriorated even further after Report 141 was published in April, prompting the Department, in July 2022, to move a small group of detainees to Unit 18 in Casuarina prison which had been designated as a juvenile detention facility."

The annual report stated that the Inspector's office has maintained an active weekly presence in Unit 18 and "while there have been some improvements there has also been a continuation of critical incidents, including: self-harm and suicide attempts; staff assaults; and significant infrastructure damage".

Speaking to the National Indigenous Times after the release of the 2021-22 annual report, Mr Ryan also noted it had become clear the merger of Rangeview Remand Centre and Banksia Hill Detention Centre in 2012 had failed.

"There is an enormous amount of work to do. I am still very concerned about youth justice incarceration at Banksia Hill and Unit 18," he said.

"We published Report 141 (on Banksia Hill) in April and it painted a pretty dire picture, and after that the situation deteriorated further and children were sent to Unit 18 in Casuarina as a result.

"There was a significant escalation in critical incidents and structure damage. Some of the young people breaches their cells and got into the roof space, there was a continuation of self-harming.

"They opened Unit 18 at Casuarina and I have very mixed views about that. They needed to do something to find a way to keep the kids secure so they were safe and the facility was safe, and Unit 18 was the least worst option but it should never have gotten to that."

Mr Ryan said the situation in Unit 18 had fluctuated since the transfer.

"There have been lockdowns and restrictions but also times where kids have been able to get about (out of their cells) for several hours a day.

"There are some additional supports such as mentors, educations, some extra welfare services but it is not designed to be a stand alone youth facility. There are still self-harm incidents, there are still critical incidents, it is far from ideal."

The Inspector said while there had been some improvements in Banksia Hill since April, "kids are getting to education, recreation and case management" but there has been a continuation of incidents.

"Just last weekend kids got on to the roof which resulted in another lockdown," he said.

The Annual report notes a "continuation of critical incidents, including: self-harm and suicide attempts; staff assaults; and significant infrastructure damage".

The Inspector noted there are many "big questions" to be answered, including whether just having one youth detention facility works.

"Looking at the history detailed in the Report it tells the story that the amalgamation of Rangeview and Banksia Hill has not been a success," he said.

"There needs to be serious consideration around alternatives to detention, particularly on Country alternatives."

Mr Ryan said a trauma-informed model of care is the key.

"It can't be just a security response. I understand what many say, that the community needs to be safe, that the kids need to be safe, but locking them down in a hard security environment model doesn't work, you will make them worse," he said.

"If there has not been a rehabilitation effort then they will be released in worse condition than when they went in."

Western Australia's youth detention crisis shot to national prominence this week with Four Corners broadcasting disturbing footage of a 14 year-old boy being pinned by three guards and crying out that he could not breathe.

Corrective Services Minister Bill Johnston said detention is a last resort under the Young Offenders Act and the majority of children convicted of offences are on community orders and not incarcerated.

"Most detainees at Banksia Hill are genuinely engaged in their rehabilitation and are actively involved in education, mental health support and recreational services," he said.

The Minister said other early intervention programs are in place to help keep young people out of detention including the Target 120 program, which focusses on a small cohort of high-risk young people identified at an early point in the justice system and aims to address underlying issues that may lead to offending.

"For those detainees and staff at Banksia Hill, I've always acknowledged that last summer was a very difficult period," he said.

He said that since the transfer of a small number of young people to Unit 17, there had been a "significant reduction" of incidents at Banksia Hill.

"Following the movement of young people to Unit 18 there was a 27% decrease in critical incidents and 72% decrease in non-critical incidents at Banksia Hill in August.

"The number of times youth offenders have assaulted Banksia Hill staff has also decreased by 85%."

Mr Johnston said the department had recruited 63 new Youth Custodial Officers this year to address staffing shortages, and that Unit 18 would cease operations as a youth detention centre at the end of June next year.

He noted that the 2022-23 State Budget included $25.1 million towards improving services for youth in detention, and an additional $15 million will be spent on an on-country residential facility for young offenders, as an alternative to detention, in the Kimberley region.

Earlier on Tuesday, the Australian Human Rights Commission urged all Australian governments to urgently address the national crisis in youth justice.