The Manus Island controversy explained

"Right now we have no water," an asylum seeker in the Manus Island centre said in a mobile telephone message to Reuters. 

"I came back to my room and they took my laptop and money and cigarettes."

Papua New Guinean police cleared the remaining asylum-seekers from Australia-run Manus Island complex on Friday, ending a three-week protest which started with some 600 men surviving on rainwater and smuggled food and supplies.

Why are there asylum seekers on Manus Island?

For four years, Australia paid Papua New Guinea, its nearest neighbour, and the tiny Pacific island nation of Nauru to house asylum seekers who attempt to reach the Australian coast by boat. They are Rohingya Muslims from Myanmar, Afghans, Iranians, Sri Lankans, Pakistanis and other nationalities.

Australia has recognised that many of the asylum seekers are refugees who cannot return to their homelands.

But it refuses to resettle anyone who tried to reach the country by boat in a policy it credits with dissuading such dangerous ocean crossings. Some whose refugee claims were denied have been forcibly sent home.

The asylum seekers that are sent to the Manus Island centre are required to wait until their asylum and resettlement claims are processed – something that can take years.

So far, no "boat person" detained on Manus Island or Nauru has been resettled in Australia.

How did this policy come about?

The detention centres are part of Operation Sovereign Borders which was established by former conservative prime minister Tony Abbott in 2013.

It is the latest incarnation of the 'Pacific Solution', devised by the-then prime minister John Howard in 2001 which allowed Australia to process 'boat people' offshore in Papua New Guinea and Nauru.

The Australian government argues the stance stops people from risking their lives at sea and breaks the people-smuggling model.

Why are they shutting these camps down? 

Last year, PNG's High Court ruled that the Manus Island centre was illegal, resulting in the closure of the camp.

The relocation of the men was designed to give the United States time to complete vetting of candidates as part of a refugee swap deal that Australia hopes will see it no longer responsible for the detention of nearly 1,400 asylum seekers who have been classified as refugees.

Those not accepted by the United States would likely be resettled in PNG or in another developing country, dashing hopes of coming to Australia.

What are conditions for people on the island like? 

Harsh conditions and reports of rampant abuse and self-harm at the camps have drawn wide criticism in Australia and abroad.

Mental health problems are well documented by charities and rights groups. Many asylum seekers suffer from depression, some have sewn their lips shut and gone on hunger strikes in protest.

Others have committed suicide.

Reports have surfaced of asylum seekers suffering from cholera and being denied access to medical treatment.

The Guardian reported the detainees were "surviving on rainwater and makeshift wells, smuggled food, and solar panels powering phones that give them a link to the outside world."

If conditions on Manus Island are so bad, why don't they want to move?

The men say they fear PNG residents on the island may attack them if they leave the camp.

One such site is the city of Lorengau where the men say they fear PNG residents on the island may attack. 

Human Rights Watch has reported that several refugees had been assaulted in the city and that they will face an increase in threats to their safety and health if the relocation were to go ahead. 

“The tragic irony is that moving these men from their squalid, guarded centre and settling them elsewhere in PNG will actually put them at greater danger," Australia Director for Human Rights Watch, Elaine Pearson said. 

Another worry is that they will be resettled in another developing nation.

What is happening now? 

Australia recently turned down an offer by New Zealand Prime Minister Jacinda Ahern to resettle some of the refugees held on Manus and Nauru.

The Australian government struck a pact with Washington under former president Barack Obama to resettle some of the asylum seekers in the US in return for taking an unspecified number of refugees from Central America.

Australia had hoped the men would have been resettled by October 31. But arranging the swap deal has slowed under President Donald Trump who called the arrangement a "dumb deal," and it's unclear whether it will go ahead.

With the closure of one camp on Manus Island, Australia and PNG are in the process of setting up new camps for current and future arrivals.