The United Nations High Commission for Refugees (UNHCR) has questioned Papua New Guinea's plans to send back asylum seekers currently detained on Manus Island.

This week PNG's prime minister Peter O'Neill told the ABC he believed most of the 1,035 asylum seekers at the Manus Regional Processing Centre were not genuine refugees and would be sent home "within weeks".

Mr O'Neill said talks were underway with Iran and Iraq to return the men home.

"I'm hoping ... [Iran] will care about the people who are in this predicament and we will all try and do the best for these people," he said.

More than 100 men have received answers to their asylum applications, but it was not clear how many asylum seekers had completed the refugee status determination process.

"Asylum seekers and refugees should not be forcibly sent back to a place where their lives are at risk," said Babar Baloch, a spokesman for the UNHCR based in Geneva.

"This act would be against the principle of non-refoulment [no forced return] under the customary international law," he said.

"UNHCR advocates that asylum seekers should be given access to a full and efficient refugee status determination process."

Asylum seekers 'deserve better than squalor, risk of violence'

The organisation Human Rights Watch (HRW) was critical of Australia and Papua New Guinea in its World Report 2015, released yesterday.

"Asylum seekers on Manus Island deserve better than to be locked up in squalor and at risk of violence," Australian HRW director Elaine Pearson said.

"Both Papua New Guinea and Australia are clearly failing in their commitment to provide safe and humane conditions for asylum seekers.

"Facilities on Manus Island are overcrowded and dirty, and asylum claims are not processed in a fair, transparent, or expedient manner, contributing to detainees' physical and mental health problems."

Six refugees have left the Australian-run detention centre and moved to a transit facility elsewhere on Manus Island to wait for an employment opportunity.

Three men were from Iran, two from Pakistan and one was from Afghanistan.

Papua New Guinea does not have a detailed policy for resettling refugees or a welfare system.

The country's immigration minister has announced plans to grant 12-month visas to refugees and help them find employment, but it was not clear what, if any, further support might be offered.

An estimated 10,000 asylum seekers and refugees who fled Indonesian control in Papua and West Papuan provinces have spent decades in PNG without being permanently resettled.

With no legal status for seeking employment, many lived in poverty and were at constant risk of eviction and violence from police.