SYDNEY, Aug 21 (Reuters) - Australia's immigration minister defended his country's tough policies on asylum seekers on Friday, saying measures including the detention of children and denial of permanent visas were needed to stop dangerous people-smuggling ventures.
Scott Morrison was giving evidence to an Australian Human Rights Commission (HRC) inquiry into the wellbeing of children in immigration detention centres on the Australian mainland and on remote islands in the Pacific and Indian oceans.
Conservative Prime Minister Tony Abbott won an election last September after campaigning heavily on tough immigration policies, which have been criticised internationally but which polls show remain popular with voters.
Asked why the average time in detention had tripled since September to almost a year, Morrison blamed the previous Labor government for allowing large numbers of boat arrivals and for blocking legislation to allow for temporary visas.
"Children being detained in facilities has been a consequence of the policies that more broadly have been effective in securing Australia's borders, restoring the integrity of our immigration programme and stopping children dying at sea," Morrison told the inquiry.
About 16,000 asylum seekers came to Australia on 220 boats in the first seven months of 2013, but the government says there has been just one "illegal" boat arrival since December. Hundreds of asylum seekers have drowned when rickety boats, mostly from Indonesia, have sunk en route in recent years.
Earlier this week, Morrison announced plans to release scores of children from immigration detention centres, following criticism from human rights advocates that detaining minors is detrimental to their mental and physical health.
Under tough laws designed to discourage refugees arriving by boat, only 150 of the 876 children currently in detention will be eligible for release. However, only those held in mainland detention centres will be eligible for release.
Children in offshore centres on the remote Pacific island of Nauru and Australia's Indian Ocean territory of Christmas Island, where critics say conditions are far worse, are not eligible.
The Royal Australasian College of Physicians (RACP) said on Friday all the children should be released, saying it was particularly concerned about the 331 minors on Nauru and Christmas Island, especially unaccompanied children.
RACP paediatrician Karen Zwi, who visited Christmas Island, said many unaccompanied children there are now displaying symptoms consistent with major depression, post-traumatic stress disorder and/or generalised anxiety disorders.
"These children have been living with uncertainty over their futures for over 12 months now and fear being transferred to Nauru," Zwi said. "If the Minister were taking his responsibility as their guardian seriously, he would not be leaving them behind bars for any longer."
Law firm Maurice Blackburn, which represents 94 babies born in detention, said Christmas Island and Nauru did not have basic medical or health services.
A former doctor at Nauru told the HRC inquiry last month that the government asked him to cover up evidence that children held in the camps were suffering from widespread mental illness caused by their confinement.
The inquiry has already heard evidence of detained children swallowing detergents, putting plastic bags over their heads and cutting themselves. (Reporting by Lincoln Feast and Jane Wardell; Editing by Paul Tait)