Ninety-five per cent of asylum-seeker children who have lived at Nauru are at risk of developing post-traumatic stress disorder, a medical team led by the Australian Human Rights Commission has found, in research that will fuel calls for asylum seekers in Australia to be saved from returning to offshore detention.

The team interviewed children at Darwin's Wickham Point detention centre, most of whom had spent several months at Nauru, and found they were among the most traumatised children the paediatricians had seen.

The researchers concluded that immigration detention at Nauru and Wickham Point centre is harmful to the physical and mental health of young children and youth.

The commission's president Gillian Triggs strongly urged the federal government not to return the children to Nauru, following a High Court decision on Wednesday that declared offshore detention was lawful. There are 267 people slated to fly back to the Pacific island, including almost 100 children and babies.

During question time on Thursday, Malcolm Turnbull deflected a demand by Greens MP Adam Bandt that the Prime Minister guarantee the children would not be sent offshore.

Mr Turnbull said the Greens did not have a "monopoly on empathy" and that softer border policies advocated by that party would result in "thousands of deaths at sea".

"Every single one of us is anguished by the prospect, by the reality of children in detention," Mr Turnbull said.

The medical team assessed children aged over eight who had previously lived at Nauru, using a childhood trauma screening questionnaire. It found 95 per cent were in the "clinical" range, which signifies a risk of post-traumatic stress disorder.

The researchers found that all children screened using the so-called "parent evaluation of development" scale were in the top two ranges for development risk, "higher than any published results for this screening tool anywhere in the world".

Experienced paediatricians Elizabeth Elliott and Hasantha Gunasekera took part in the commission's visit to Wickham Point in October.

Dr Gunasekera said they were "deeply disturbed by the numbers of young children who expressed intent to self-harm and talked openly about suicide and by those who had already self-harmed".

Professor Elliott said: "many of the children had palpable anticipatory trauma at mention of return to Nauru ... Nauru is a totally inappropriate place for asylum seeking children to live, either in the detention centre or in the community."

The doctors warned no child detained on the mainland should be sent to Nauru under any circumstances.

Immigration Minister Peter Dutton and his department were provided with the findings in November. Mr Dutton has since indicated that the asylum seekers would be quickly returned to Nauru following the High Court decision.

On Thursday the minister said the government would examine each case individually, but warned that unauthorised boat arrivals found not to be refugees would be sent to Nauru, if they did not return to their country of origin.

The researchers found that detention centre staff lacked understanding of the "cumulative impact of one episode of trauma upon another".

"Some children had witnessed atrocities at home, survived a traumatic boat trip, had been moved between several onshore to offshore detention centres, were traumatised by the presence of uniformed guards and actions such as head counts and had palpable anticipatory trauma at mention of return to Nauru," the report said.

"There was a mismatch between the level of mental health and the level of paediatric psychiatrist and psychologists with appropriate training in managing children. This must urgently be addressed."

Parents reported concerns about their own and their children's health.

"Examples include: reports of recurrent abdominal pain, headaches, nausea, vomiting, poor feeding, poor sleeping and poor weight gain in young children," the report said.

A 12-year old had chronic hypertension and another child with a metabolic disorder diagnosed in his homeland had not yet seen a paediatrician in Australia.

A child with autistic spectrum disorder required early intervention and a 2-year-old with no speech needed audiology, speech pathology and paediatric assessment.

Illustrations by the children are stark indicators of their anguish. One by a 7-year-old girl shows a small, bloodied body lying at the base of the building. It is captioned: "I jumped from the house to the ground and I died. My mum and dad are crying."

Wickham Point offered only one or two excursions a month, but some excluded children and the presence of guards was "stigmatising", the report said.

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