The UN’s human rights office on Friday urged Australia to reconsider its policy of shipping asylum-seekers to Papua New Guinea and detaining them there, after rioting at a holding centre left one person dead.

The UN's human rights office on Friday urged Australia to reconsider its policy of shipping asylum-seekers to Papua New Guinea and detaining them there, after rioting at a holding centre left one person dead.

Ravina Shamdasani, spokeswoman for the UN high commissioner for human rights, said this week's violence at the Manus Island facility had thrown the spotlight on a wider problem.

Manus Island and another centre in the tiny Pacific nation of Nauru are the core of Australia's punitive off-shore detention policy, which has been repeatedly condemned by the UN and human rights groups.

Under the scheme, which Australia says is aimed at deterring people-smugglers, any asylum-seeker arriving by boat or intercepted at sea is transferred to Manus or Nauru for processing and permanent resettlement outside Australia.

"We stress the obligation of Australia, PNG and Nauru to ensure that the human rights of asylum seekers are protected in accordance with international standards," Shamdasani told reporters.

"The practice of detaining migrants and asylum-seekers arriving by boat on a mandatory, prolonged and potentially indefinite basis, without individual assessment, is inherently arbitrary. Moreover, alternatives to immigration detention should always be considered," she added.

An estimated 1,340 asylum-seekers are currently being held at Manus Island.

Tensions with locals have reportedly spiked, and the detainees recently learned that if their asylum claims were approved they would only be allowed to settle in Papua New Guinea, not Australia.

Thirty-five asylum-seekers broke out of the facility on Sunday and several were injured.

In more rioting the following night, one person was killed and 77 injured, 13 of them seriously.

"While the precise circumstances are not yet clear, it is alarming to see violence against the very individuals who seek protection," said Shamdasani, adding that the incident underscored the need for independent monitoring of the facilities.

While welcoming a probe by Australian and Papuan New Guinean authorities, she said it must examine reports that private security forces were involved in the violence.

"We stress that states maintain their human rights obligations when they privatize delivery of services such as security, and must take steps to investigate, redress and punish human rights abuses by third parties," she said.