Aboriginal teen dies by suicide in Perth youth prison

An Aboriginal teenager has died by suicide at a youth prison in the Australian state of Western Australia (WA).

The 17-year-old had spent only two days in custody before he was found unresponsive in his cell on Thursday and could not be revived, the state's authorities say.

Aboriginal and Torres Strait Islander people are the most disproportionately incarcerated people on the planet and also die in custody at far higher rates than non-Indigenous Australians.

Deaths in juvenile detention centres, however, are rare, and this is the second in the state in under a year.

"This is a horrible, horrible event," WA premier Roger Cook said when announcing an investigation on Friday morning.

"Clearly a failure has taken place and we will undertake the important task of understanding the circumstances."

The teenager - who has not been identified - had arrived at the centre on Tuesday in an intoxicated state and so had been placed in an intensive supervision unit due to concerns for his health.

However there were no signs of mental distress, Commissioner of Corrective Services Brad Royce told reporters.

The boy had spent most of Thursday afternoon outside of his cell, and had been checked on by staff ten times in the hours before his death.

The incident comes ten months after 16-year-old Cleveland Dodd became the first juvenile to die in a WA youth detention centre.

Investigators this year cleared prison staff of serious misconduct, but found significant failures in the lead up to Dodd's death.

Mr Royce said he had reviewed footage from the detention centre on Thursday and was satisfied the response of staff in this case was "appropriate".

The condition of youth jails across the state had improved since Dodd's death, Mr Cook said.

“I have more confidence than ever before in terms of the way we are managing our juvenile detention facilities,” he said.

Australia has been under international pressure to raise the age of criminal responsibility - which in some state is as low as 10, and disproportionately affects First Nations kids.

The conditions in youth detention centres have also drawn international criticism, including from the UN, which claims they breach international law, including the Convention on the Rights of the Child.

"This was a preventable death. How many times, by how many experts, does the WA government need to be warned about the dangers of their youth detention centres?" Amnesty International's Kacey Teerman said in a statement.

Responding to questions about these long-held concerns, Corrective Services Minister Paul Papalia on Thursday said there was "no obvious, immediate, systemic change" needed.

"We’re responding with anything we can and anything that's required."

If this story has raised issues for you, you can call Lifeline on 13 11 14, if you're an Aboriginal or Torres Strait Islander you can call 13-yarn on 13 92 76.