WA's Corrective Services Minister has been condemned by legal professionals for comments criticising judges and magistrates over their sentencing of juvenile offenders.

Paul Papalia, who has been under pressure for a series of comments and actions in his portfolio, including last week arguing children in youth prisons didn't need air-conditioning, even as the state suffered extreme temperatures, has said he stands by comments a traumatised Indigenous child should receive a harsher sentence, blaming in part "activist" judges.

His latest attacks were aimed at Judge Wendy Hughes, who last week told a 17-year-old who pleaded guilty to three counts of assaulting staff while in detention, the system had "well and truly failed" him.

The child, who is held in the notorious Unit 18 inside of the adult maximum-security Casuarina Prison, suffers from a series of complicated and debilitating mental impairments, including ADHD, PTSD and a conduct disorder resulting in impulsive behaviour and a lack of consequential thinking.

The child was given a 12-month extension on his sentence for a series of offences, including aggravated armed robbery and car theft, but Judge Hughes declined to impose extra custodial sentencing on him for three counts of assaulting an officer while in custody.

She said the boy had "exhausted all of his coping mechanisms" after being traumatised by being held in custody - including unlawful lockdowns for up to 24 hours a day - which had led him to become suicidal.

However, Mr Papalia said it was "not right" the boy faced no further consequences for assaulting the officer.

"There was some failures with that particular incident, and it was the officer who was assaulted by a juvenile detainee and then there was no consequence," he said on Tuesday.

He doubled down on his criticism on Wednesday, with The West Australian reporting Mr Papalia refused to answer if he had read the transcript of Judge Hughes' findings.

"There's been a lot of commentary from people in the judiciary in a bit of an activist manner," the Minister told reporters.

"If you assault an officer - a youth custodial officer or a prison officer going about their lawful duty - there should be a consequence."

Judge Hughes could legally not impose further punishment for the assault charges "because of the circumstances in which he is being detained" and citing Section 67 of WA's Young Offenders Act.

Mr Papalia's comments prompted criticism from Noongar human rights law expert and legal academic Hannah McGlade, who argued he shouldn't be in a role that was incumbent on care towards Indigenous people due to the disproportionate level of Indigenous incarceration in the state.

"I think Mr Papalia is completely unfit to hold the role of corrections minister in making such attacks on the Children Court Judge and evidencing such a poor attitude towards Aboriginal youth," Dr McGlade said.

Citing the death of 16-year-old Cleveland Dodd last year in Unit 18, Dr McGlade said the minister's comments show a "lack of concern to the lives of Aboriginal children."

"He seems to think that traumatised children and Aboriginal children should be further treated in punitive and hostile manner for their so-called crimes," Dr McGlade said.

"We're failing completely in terms of youth justice and it's a significant cost to our state.

"'Tough on crime', yet failing Aboriginal children and Aboriginal families. [We're] failing everyone; failing society."

The WA Law Society blasted Mr Papalia for his comments, with President Paula Wilkinson arguing the minister's continual attacks on judge's was "compromising our judicial independence".

"[T]here are very few appeals against Children's Court sentences, suggesting courts routinely get it right," Ms Wilkinson said.

"It is not the Minister's role to criticise or undermine the public confidence in our justice institutions."

The Children's Court has repeatedly found the WA government continues to detain children in solitary confinement. Evidence has shown this is a significant cause of harm, and only exacerbates recidivism. The conditions inside Unit 18 have previously been labelled a "barbaric dungeon where children are deprived and dehumanised" by Children's Court president Hylton Quail.

The WA Law Society said Unit 18 offered no rehabilitative effect and its effects on children left the community less safe.

"This situation is entirely the government's responsibility (and failure) and the Supreme and Children's courts have found repeatedly over the last 2 years that the department of corrective services has acted unlawfully in the way it manages children in detention, causing them short- and long-term harm," Ms Wilkinson said.

The ABC reported last week that Judge Hughes had to balance the justice system's seemingly inability to care for the child, along with his ADHD and conduct disorder diagnoses, with the risk he posed to the community, saying it "broke her heart" to see him back before the court.

"When he gets out it's unlikely the community's going to be any safer … and that is a very sad point [to have reached]," she said.

The child had previously attempted to self-harm by eating glass, whilst previous footage captured by the ABC showed him push custodial officer off a buggy being used to transport him because he wanted to find a fence to commit suicide. In another incident, the child was placed in a "figure-four" hold at Banksia Hill, which was described as an "unacceptable and outrageous case of child abuse."