The Australian government has come under increased pressure to overhaul its immigration laws after a report published Wednesday by the country’s Human Rights Commission alleged that hundreds of refugee children are suffering from severe mental illness as a result of prolonged detention at camps like those in Papua New Guinea and Nauru.

According to the report, titled “The Forgotten Children,” the government-funded commission found that in the 15-month period between January 2013 and March 2014, nearly 300 of the over 1,100 children being held in onshore and offshore detention centers had committed or threatened to commit self-harm, and nearly 30 children were sexually assaulted. The children involved in self-harm were between 12 to 17 years old.

australia detention_1 Children in detention by age, 31 March 2014 Photo: Australian Human Rights Commission analysis of data from Department of Immigration and Border Protection

Moreover, the commission found that while the average duration of detention of these children was 14 months in October last year, it has since increased to 17 months.

“The report cites medical data that shows 34 percent of children have been diagnosed with serious mental disorders. The report also found that the lengthy detention of children breaches Australia’s international obligations under the Convention on the Rights of the Child (UNCRC),” Gillian Triggs, president of the commission, said, in a statement released Thursday.

Under the UNCRC, children are supposed to be detained only as a measure of last resort and, if they are detained, an immediate review of the legality of the detention should be launched by the government.

“Given the profound negative impacts on the mental and emotional health of children which result from prolonged detention, the mandatory and prolonged detention of children breaches Australia’s obligation under article 24(1) of the Convention on the Rights of the Child,” the commission said, in the report. “Children and their families frequently describe detention as punishment for seeking asylum.”

Under its strict anti-immigration policy, Australia currently detains all asylum seekers arriving by boat, holding them in offshore processing camps. Following the recent influx of refugees from conflict-hit zones in the Middle East, the Australian government has faced severe criticism from several human rights groups over the conditions in these detention camps.

australia detention Number of children in detention, July 2004 to January 2014 Photo: Australian Human Rights Commission analysis of data from the Department of Immigration and Border Protection

“The findings of the Australian Human Rights Commission report confirm what is already known globally -- detention is a dangerous place for children and can cause life-long harm.  You can’t keep children safe in detention,” Unicef said, in a statement released Thursday.

However, Australian Prime Minister Tony Abbott dismissed the commission’s findings and accused it of indulging in a “blatantly partisan exercise,” according to media reports. Last week, Abbott narrowly survived a no-confidence motion launched by critics from within his party to challenge his leadership.

“It would be a lot easier to respect the Human Rights Commission if it did not engage in what are transparent stitch-ups,” Abbott reportedly said. “This is a blatantly partisan politicized exercise and the Human Rights Commission ought to be ashamed of itself.”