Warning: this story contains the name of someone who has died.

WA's Children's Court president Hylton Quail has slammed the state's youth detention facility, Unit 18, in the wake of the death in custody of 16-year-old Aboriginal boy Cleveland Dodd, who was found unresponsive in his Unit 18 cell days before his death in hospital.

The unit, a youth detention centre within Casuarina maximum security adult prison, has been criticised by a range of legal experts and advocates since it began operating last July, including Judge Quail on previous occasions.

On Friday Judge Quail condemned the facility while sentencing of a 15-year-old who was detained there on remand, saying the environment made the boy more of a danger to the community when he came out than before he had gone in.

The ABC reported Judge Quail said it seems "those who administer Unit 18 do so with impunity".

"Those conditions in Unit 18 and the way that you have been treated whilst you have been in custody have been of no rehabilitative effect," he said.

"You have therefore been released into the community more dangerous than when you went in."

The ABC reports the boy was being sentenced for a number of offences including aggravated burglary and stealing along with offences committed against guards, staff and property while detained in Unit 18.

The teenager had spent time in Banksia Hill and Unit 18 before, with his most recent stint in Unit 18 starting in August.

Judge Quail noted that during this recent detention, the boy had been locked in his cell for 22 to 23 hours every day.

"As this court has said as long ago as February of last year, when you cage children and treat them like animals, you should expect when the door is opened that they will behave in that way, which is not to excuse what you do," he said to the boy at sentencing.

"There is no doubt … that those conditions in Unit 18 put you in a group of boys … who are subject to by far and away the worst conditions of incarceration of any group in this state, worse than any adult prison.

"It is clear that you have been brutalised and alienated and in turn, you have reacted against those who are responsible — directly responsible for looking after you in the detention centre."

Last October Judge Quail described the detention of children in Unit 18 at Casuarina maximum security adult prison as "barbaric", "cruel" and "a form of child abuse", and warned the state government it could be found in contempt of court for continuing to detain children in an adult prison.

The ABC reports that on Friday Judge Quail said it was very significant that continuing lockdowns came after a court ruling in July deeming them unlawful.

"What that means from my perspective, is that those who were in charge of Unit 18 – not the guards who are working with you, the people in charge of unit 18 – continue to ignore what this court has said," he said.

"I am lost for words that nothing has changed since then and the situation in Unit 18 seems to be getting progressively worse. And that since that decision (in July), you have been confined in your cell in the way that you have, and in particular on those six days I have identified, for 24 hours on each of those days."

In August last year, the Supreme Court of Western Australia ruled the lockdown of a 14-year-old boy in a cell for at least 20 hours per day on 26 occasions across four months in Banksia Hill Detention Centre was unlawful.

National Indigenous Times has contacted WA's Minister for Corrective Services for comment.