The inquiry will accept submissions and conduct public hearings, with those who are now Australian citizens encouraged to tell of their experiences as children.

She has also expressed frustration at the level of co-operation from the government in giving information on issues, including levels of self-harm in detention, and at the blanket denial that Australia's treatment of children in detention is in breach of international treaty obligations. This was a key finding of the last report.

Although a similar inquiry a decade ago resulted in a significant drop in the number of children in detention, Professor Triggs conceded that the political climate was more difficult now than when the report ''A Last Resort?'' was released in April 2004.

The inquiry will investigate the ways in which life in immigration detention affects the health, wellbeing and development of children. It will also examine separation of families across detention facilities and the adequacy care of unaccompanied children in the detention network.

While non-government human rights bodies have been able to visit the detention centres on Nauru and Manus Island, Professor Triggs said it would be more difficult for the government to deflect human rights concerns if they were expressed by the Australian statutory body with a mandate to protect human rights. She conceded that Mr Morrison's decision was consistent with the attitude of the former Labor government, saying she had hoped the minister would exercise his discretion to facilitate a visit, given Australia's responsibility for those it transferred to aid-dependent Nauru.

''The minister is simply refusing to allow me to go as president but, as you'd expect in a democracy, I'm welcome to go as a private citizen,'' Professor Triggs said. ''There would be no point [in that] because I couldn't then use my experience as a private citizen inform my role as the president of the commission.''

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Mr Morrison has signalled that he will co-operate with the inquiry and insisted he is continuing to ''engage'' with the commission. ''I met with the Human Rights Commissioner not that long ago and we discussed a whole range of issues and I am happy to keep meeting with them,'' he said.

''She has a job to do, I have got a job to do, you've got a job to do - and we'll all keep doing our jobs and my job is to stop the boats and that's what is happening,'' he told Sydney broadcaster Ray Hadley.