Australian Immigration Minister Scott Morrision has dismissed findings by the UN High Commissioner for Refugees (UNHCR) which reported that Australia's treatment of asylum-seekers fails to meet international standards.

Following UNHCR inspection of detention centres at Nauru and PNG's Manus Island in October, the UN body has said that asylum-seekers are being subjected to arbitrary, mandatory and indefinite detention in unsafe and inhumane conditions that failed to meet international standards.

Dismissing the allegations made by the UNHCR, Mr Morrison said the UN agency had a long track record of opposing offshore processing.

"The criticism of Papua New Guinea and Nauru is quite overstated," he told reporters in Sydney.

"They're working very hard to put their systems in place," he said.

The immigration minister said the offshore processing centres are in a "transitional phase" and pointed out that he was in talks with Nauru and PNG for further improvements of the centres.

Blaming the former government of having re-established the offshore processing centres in a "muddled and incompetent" way Mr Morrison said the "constant chopping and changing" presented a real challenge for partners in Nauru and PNG.

Mr Morrison said the government was looking at the funding issues for managing these centres.

"In our first 100 days, it's our expectation that we would have more than doubled the capacity of offshore processing and addressed the quite serious funding issues that remained unaddressed in the previous government."

Australian Greens Senator Sarah Hanson-Young, meanwhile, citing the UNHCR report said it demonstrates why children and pregnant women should not be detained in Nauru.

"The government's secret war on refugees is going into overdrive, but the world is watching on," she said.

As reported earlier, the Australian Medical Association (AMA) of the Northern Territory (NT) has proposed to report Mr Morrison to the Department of Child Protection as being guilty of child abuse for detaining children in offshore detention centres.