In the wake of the Australian Human Rights Commission report into children in detention, the peak professional body for psychiatrists said it “opposes the routine, prolonged and indefinite detention of child asylum seekers under the policy of mandatory detention”.

“Detention is detrimental to development and mental health and has the potential to cause long-term damage to social and emotional functioning,” the position statement said.

“Unaccompanied minors and families with children are particularly vulnerable. Detention should only ever be used as a last resort, with the child’s best interests in mind, for the shortest possible length of time.”

Australia’s mandatory detention of children is in breach of the United Nations Convention on the Rights of the Child, the college said.

Australia is legally bound by the convention, having ratified it in 1990.

RANZCP president Dr Murray Patton said psychiatrists were extremely concerned about the situation of children detained in Australia and overseas.

“The statistics in the recent ‘Forgotten Children’ report are extremely alarming,” Patton said.

“The level of mental health disorders recorded indicates there will potentially be an ongoing need to support and treat these children even once they leave detention whether in Australia or elsewhere. Traumatic events, such as being detained for a prolonged period, can lead to mental illness in adults.”

“The preferable length of time in detention for a child who is undergoing health and safety checks is less than 72 hours. This is quite a contrast to the 14 months reported recently.”

Releasing the Human Rights Commission report this month, the commission president Gillian Triggs said when the report was first handed to government, last October, the average length of detention of a child in Australia’s immigration detention regime was 14 months.

“Today, their detention has lengthened to 17 months.”

The Triggs report has been hugely controversial, with the government accusing Triggs of a partisan “transparent stitch-up”.

And Senate estimates unearthed details of a quiet job offer from the government in an attempt to move Triggs on from her statutory five-year role because ministers had “lost confidence” in her impartiality.

Currently, there are 126 children in detention in Australia, and 116 held on Nauru. Sixty eight of the children detained in Australia will be moved back to Nauru once their medical care – or the medical care of a relative – ends.

Nineteen children in Australia are being held in indefinite detention with no prospect of release because of an adverse security assessment from Asio against a relative, or because of a ministerial decree.

The number of children in detention peaked in September 2013 under Labor, at 1,992. The immigration policies of both the Coalition and Labor mandate the detention of child asylum seekers who arrive by boat.

Peter Young, the former director of mental health for International Health and Medical Services (IHMS), the private contractor that provides medical care to detention centres, said “it is clear that detention is inherently damaging for children”.

“There is no way around it, because it is designed to be restrictive, it is designed to oppress and create uncertainty.”

Children in immigration detention are held in harsh, often dangerous, conditions Young said. They are also face exposure to trauma in detention: assaults committed against them or family members, high rates of mental illness in those around them, and acts of self-harm by other detainees.

But beyond the conditions of detention itself, “the arbitrariness, the uncertainty, of detention, these are the factors that are especially damaging.”

Young said the indefinite detention of children was particularly troubling.

“When detention is open-ended and indefinite like that, it is really saying ‘there is no hope for a better life’. When that is being said to a child growing up in these difficult conditions, it is hard to think of anything more damaging.”

Young said he welcomed the college’s position statement, and its support for mental health professionals who have spoken out about detention conditions. “Psychiatrists’ duty of care is to their patients. They have a role in advocating for their patients, and for a better system.”

On Nauru, a large-scale protest is planned for this weekend. Children and adults have already begun a protest of non-cooperation. They have boycotted school and adult English classes and are refusing to speak with case managers. Others have quit jobs or gone on strike.

One resettled refugee wrote that he, and others, were protesting because they could not face the prospect of resettlement on Nauru.

“Last night there was a hot rumour that an agreement for long settlement has been signed yesterday between immigration and Nauruan government with [a] champagne party. Once again refugee cattle has been sold by the fucking Nauruan government just for money. And that all money is tax pay money of Australian public.”

“Now the entire situation compelled us to protest. Because ‘enough is enough’ … at last, we have no option instead of protest for our right.”

 The immigration minister Peter Dutton was in Nauru last week. He was negotiating a five-year plan for asylum seeker processing and refugee resettlement, according to the Nauruan government.

There were no reports of champagne, but the minister’s dinner with the Nauruan president Baron Waqa was interrupted by a noisy but peaceful protest by refugees chanting: “Freedom, justice, shut down offshore [detention]”.

The Nauru detention centre is moving to an “open centre” model where asylum seekers will be free to move outside the wire fence of the camp. But they have been given a list of 12 locations in Nauru where they cannot go, including the parliament, courthouse, hospital, all schools, any harbours or ports, or the airport.

They face fines or jail for breaching those conditions.

“An open centre will give transferees more opportunities to engage with the Nauruan community before their refugee processing has been completed,” Dutton said, “allowing genuine refugees to ultimately integrate seamlessly into the community.”

The Guardian