Australia's human rights watchdog has opened an inquiry into the detention of more than 1,000 children under punitive government policies that have seen asylum-seekers arriving by boat taken to Pacific camps.
The probe, launched on Monday, will examine the impact of mandatory detention on more than 1,000 asylum-seeker children being held in immigration facilities in Australia, said Gillian Triggs, head of of the Australian Human Rights Commission.
More than 100 children are also being held on far-flung Nauru.
Triggs said: "These are children that, among other things, have been denied freedom of movement, many of whom are spending important developmental years of their lives living behind wire in highly stressful environments."
The inquiry will examine whether Australia is in breach of international child protection obligations and measure progress on the issue over the past decade.
A similar investigation was held in 2004 into the then-government's "Pacific Solution" of detaining asylum seekers arriving by boat on Nauru and Papua New Guinea's Manus Island.
The number of children held dropped markedly following public outcry over the 2004 inquiry's findings.
"The political circumstances are perhaps different today, the public has in some respect become used to the idea that we keep children in detention. So maybe it would be optimistic to imagine that we'd have quite the same impact this time around," Triggs said.
The 2004 inquiry's report found mandatory detention of children was "fundamentally inconsistent" with Australia's international human rights obligations and minors locked up for long periods of time were at "high risk of serious mental harm".
During their time in detention - an average of almost two years - children were exposed to hunger strikes and violent acts of self-harm as well as wild riots which were contained with tear gas and water cannon, the report found.
There were self-harm incidents including attempted hangings and lip-sewings among juvenile detainees and some were diagnosed with depression or post-traumatic stress disorder after their release.
Education provided to children in detention fell "significantly short" of community standards and there were broad-ranging health concerns including the extreme climate at remote facilities, overcrowding and unsanitary conditions.
Scott Morrison, the immigration minister, rejected Triggs' claim, saying there were so many children in detention because of border security "failures" by the previous government, which was voted out in September.
"There were over 1,000 children held in detention when we came to office... because over 50,000 people turned up on illegal boats on Labor's watch," he said, referring to the name of former Prime Minister Kevin Rudd's party.
The harsh Pacific detention policy was revived last year by Rudd, who made it tougher still by mandating that anyone who arrived by boat would be permanently settled in Papua New Guinea or Nauru.
Morrison said the government would cooperate with the inquiry and any recommendations would "be treated with respect and considered".