The United Nations Refugee Agency (UNHCR) has called for the immediate transfer of refugees and asylum seekers out of the Australian-run detention camps on both Manus Island and Nauru.

A team from the UNHCR was on Nauru when Omid Masoumali, a young Iranian man who died later in a Brisbane hospital, set himself on fire.

Days later a 21-year-old Somalian woman set herself alight and remains in a critical condition.

Sorry, this audio has expired Richard Ewart speaks to the UNHCR.

"There is no doubt that the current policy of offshore processing and prolonged detention is immensely harmful," UNHCR said in a statement.

"There are approximately 2,000 very vulnerable refugees and asylum seekers on Manus Island and Nauru [and] despite efforts by the governments of Papua New Guinea and Nauru, arrangements in both countries have proved completely untenable."

It added: "UNHCR's principal concern today is that these refugees and asylum seekers are immediately moved to humane conditions with adequate support and services."

Over the last few years, the UNHCR has undertaken regular visits to offshore processing sites to monitor the situation of refugees and asylum seekers, including seven separate occasions to Nauru since 2012.

Recent events 'symptomatic of hopelessness'

Catherine Stubberfield, from the UNHCR's regional office in Canberra, told the ABC's Pacific Beat program the recent events are part of a continuum of deteriorating mental health witnessed over several years in Nauru that have reached a breaking point.

"These are highly predictable outcomes of prolonged detention, and they're really symptomatic of the fact that people have now lost all hope," she said.

"When we talk about these incidents, we need to think about how these people feel — having fled trauma, persecution, war — thinking that they've come to a place of safety."

Ms Stubberfield added that such trauma combined with being held in a highly securitised environment in a constant state of uncertainty — where individuals "have no agency over their lives" over the course of many years — has directly contributed to the events of recent weeks.

Following the incidents, Australia has alleged that publicity surrounding these cases exacerbates the situation, but Ms Stubberfield maintains that the Australian people do not have a good picture of what is actually taking place in Manus Island and Nauru due to a continued media blackout.

"What we [UNHCR] really see on our monitoring missions is that people live in poor physical conditions, they're overcrowded, they don't have access to basic services ... they're not getting the support they need," she said.

"I think rather than detract from that, in terms of speaking about the impact of publicity, we need to speak about the reality of the immense damage done by the current offshore detention and processing policies."

But asked where offshore refugees could be moved, given the response of the Australian government and the upcoming election season, Ms Stubberfield said the UNHCR doesn't prescribe suitable locations, it only prescribes suitable conditions.

"That's a matter for the government concerned ... in this case, the Australian Government."