Prime Minister Tony Abbott has slammed a report into the mental health of children in immigration detention, calling it a “blatantly partisan politicised exercise”.

Speaking on 3AW radio on Thursday morning, Mr Abbott said the Australian Human Rights Commission “ought to be ashamed of itself” following the inquiry.

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The 315-page report, released by the government on Wednesday night, called for a royal commission into the long-term impacts of detention on children.

It found more than a third of children in detention in the first half of 2014 were assessed as having serious mental health disorders.

Mr Abbott accused the commission of being absent during Labor’s term as government.

“Where was the human rights commission during the life of the former government when hundreds of people were drowning at sea?” Mr Abbott said.

The prime minister also said he had no guilt “whatsoever” when detaining children.

“The most compassionate thing you can do is stop the boats. We have stopped the boats,” he said.

A drawing by a child in detention. Photo: AAP

He even went as far as to suggest the human rights commission congratulate former Immigration Minister Scott Morrison.

“I reckon that the Human Rights Commission ought to be sending a note of congratulations to Scott Morrison saying ‘well done mate, because your actions have been very good for the human rights and the human flourishing of thousands of people’.”

“There were almost 2000 children in detention in the middle of 2013 under the former government’s watch. There were almost 1400 children in detention at the time of the election that number is now under 200.”

The long-awaited report recommends a royal commission be set up to examine “the long-term impacts of detention on the physical and mental health of children in immigration detention”.

It would also investigate “reasons for continued use of this policy since 1992, including offshore detention and processing” and “remedies for any breaches of the rights of children that have been detained”.

The report also recommends that all children and their families in detention in Australia and on Nauru be released into the Australian community within the next four weeks and that all detention facilities on Christmas Island be closed.

In a statement Attorney-General George Brandis said he was “disappointed and surprised that the Australian Human Rights Commission did not start its inquiry until 2014, considering the problem was at its most acute prior to the 2013 election, when the number of children in detention peaked at 1,992 under the former Labor Government in July 2013”.

Senator Brandis also rejected the report’s finding that the Commonwealth is in breach of its international obligations under the Convention on the Rights of the Child.

Greens senator Sarah Hanson-Young condemned the report being tabled so late in the day.

“The Government tried their hardest to bury this report today,” she said.

“They’ve waited to the very last moment to table what is a very serious report into what is institutionalised child abuse in this country.”

– with ABC