Australia's peak non-government mental health organisation has described the situation in Western Australia's children's prison as "a picture of trauma, disadvantage, distress and injustice".

In a statement issued Thursday, Mental Health Australia chief executive Dr Leanne Beagley urged governments across Australia to get children under 14 out of prisons by raising the age of criminal responsibility.

"This week we cannot have avoided being made aware of the treatment of primary school aged child 'prisoners' in a Perth justice centre," she said.

"This was a picture of trauma, disadvantage, distress and injustice. And it was not the first time.

"The eyes of the world are on Australia in relation to action on this deeply troubling situation."

Dr Beagley noted that at the most recent United Nations Human Rights Council Universal Period Review of Australia's compliance with international human rights charters it has signed, the majority of member states (29 of 47) urged the country to raise the age of criminal responsibility.

The Republic of Maldova representative urged: "[That Australia] adjust the national child justice system in line with the Convention on the Rights of the Child, in particular raise the minimum age of criminal responsibility from 10 to 14 years of age."

Dr Beagley reflected on a prison visit she made on Remembrance Day.

"I went into Port Phillip Prison in Melbourne for a ceremony to mark the work of my late husband as a prison chaplain for 15 years, and that of his colleague who also recently passed away. The impact of the pandemic had prevented such an occasion until now," she said.

"After the RAT tests, security screening and multiple doors needing to be locked and unlocked both families made our way to a place marked by memorial plaques and a beautiful garden designed carefully distract. There followed a ceremony and a 'celebration' with work colleagues.

"However meaningful this event was for us and our family, this is not and should never be a place for children."

WA Premier Mark McGowan has ruled out raising the age of criminal responsibility and has rejected calls to close down Banksia Hill, including from former Inspector of Custodial Services Neil Morgan.

Earlier this week WA Law Society president Rebecca Lee, in reference to the transfer of detainees from Banksia Hill to Casuarina, said "sending children to the main maximum-security prison in WA is not the right solution and there needs to be a rethink".

"The WA Government needs to urgently look at how it can redirect funding to the programmes that work to reduce the root causes of crime before behaviour escalates, and how to house children appropriately when either bail is inappropriate, or a custodial sentence is to be imposed," she said.

"The system is broken if juvenile detainees are being housed in conditions described as cruel and punishing, and as having no rehabilitative effect... This should not be the intent or the impact of our justice system."