SYDNEY • The last asylum-seeker child in Australian mainland detention has been freed, the government said yesterday, although dozens of others are still being held on the remote Pacific island of Nauru.

Under Canberra's harsh immigration policy, asylum-seekers who try to reach Australia by boat are turned back or sent to Pacific camps in Nauru and Papua New Guinea, where they are held indefinitely while their refugee applications are processed. They are blocked from resettling in Australia even if found to be refugees.

Canberra has been under pressure from rights groups to release children from the centres, with doctors and whistle-blowers saying the detention of asylum-seekers has left some struggling with mental health problems.

"We've succeeded since the change of government (in September 2013) not only in stopping the boats, but we've also succeeded... that there are now no children who'd arrived unlawfully by boat in detention," Australian Prime Minister Malcolm Turnbull told Sky News.

The announcement means the children have been moved to community detention, where asylum- seekers waiting for their refugee applications to be processed live within the community. They are usually allowed to move around freely.

Detention levels for asylum-seeker children in immigration centres have fallen from a record number of almost 2,000 in June 2013.

Deputy Labour opposition leader Tanya Plibersek welcomed the news, but said there had "been a massive expansion of time that people stay in detention in Australia".

The average time for people being held in mainland detention facilities is at its highest level - 464 days - since records were kept from January 2012, according to immigration department figures.

Meanwhile, another 50 children were still being held at the Nauru camp, although the Pacific government said in October the asylum-seekers there are free to roam around the tiny nation.

AGENCE FRANCE-PRESSE