Australia defended its tough immigration policy on Tuesday in the face of criticism from human rights group Amnesty International that alleged its treatment of asylum seekers on the Pacific island of Nauru amounted to "torture" and a "systematic regime of neglect and cruelty."

Around 400 men, women and children are currently held in indefinite detention at the Nauru facility - one of two offshore processing centers that Australia has used since 2013 to house asylum seekers intercepted at sea.

Under its policy, the Australian government blocks asylum seekers arriving by sea from being resettled in Australia, even if they are found to be genuine refugees after processing at centers like Nauru.

Facing the media on Tuesday morning, Australian Prime Minister Turnbull rebuffed the allegations, telling the Australian Broadcasting Corporation (ABC): "I reject that claim totally. It is absolutely false."

Turnbull defended his government's commitment to improving standards in the detention facility, saying: "As far as Nauru is concerned … there is a very substantial investment there, to improve the circumstances of the people that are there."

'Absolute despair'

Titled "Island of Despair," Amensty's detailed report was based on research and field work in Nauru between July and October this year. It alleged that the prison-like conditions in the detention facility were driving asylum seekers to "absolute despair" with an "epidemic of self-harm."

"We don't come to these conclusions easily," Amnesty's senior director of research Anna Neistat told reporters on Tuesday. "This is not an isolated incident, [it] is done deliberately with a clear purpose of creating a deterrence, to punish."

'Compassionate and strong' protection policies

Prime Minister Turnbull talked up his achievements on immigration, however, describing his government's commitment to its border protection policies as "compassionate and strong."

"What we've been able to do is to stop the boats, no deaths at sea. We have reduced children in detention from almost 2000 when we came into office (in 2013) to zero."

But Neistat insisted that Turnbull's claims aren't "technically not true" since deaths continue to occur in international waters, just not near Australia. "They are saving lives, but at what cost?" she asked.

Nauru government rejects report

The Nauru Government declined to respond to the Amnesty report, instead singling out a report aired simultaneously on ABC TV containing similar allegations. It quoted numerous children detained on the island.

"It was clear these children were coached," the government said in a statement, calling the ABC report "biased political propaganda and lies" and "an insult to the people of Nauru."

The United Nations (UN) issued its own fresh criticism of Australia's human rights record on Tuesday, singling out its policy of imposing maximum jail terms of two years for detention center workers who reveal any details of its operation, describing the policy as a curtailment of free speech.

tm/jm (AFP, Reuters, dpa)