23/11/2017 9:02 AM AEDT | Updated 23/11/2017 3:23 PM AEDT

"Move, Move": PNG Police Enter Closed Manus Detention Centre

"It's too much tension and the refugees are extremely scared," one asylum seeker reported.

PNG Police and Immigration have moved into the closed detention camp on Manus Island and started moving the hundreds of men still inside the facility, arresting award winning journalist and asylum seeker Behrouz Boochani.

Shouting 'Move! Move!' through microphones at the men, some of whom have climbed onto rooftops to escape, immigration authorities and Papua New Guinea police moved in on the camp on Thursday morning.

It's been almost four weeks since Papua New Guinea authorities closed the detention camp, shutting off electricity, water and supplies of food.

"We are blockading right now," said asylum seeker and multi-award winning journalist Behrouz Boochani on Thursday morning. He has since been detained by police. Boochani has been a vital source of information from inside the centre, where he has been detained for more than four years.

"I am tweeting from a toilet right now."

The Media Entertainment and Arts Alliance has condemned his arrest, which came just weeks after the PNG government threatened to round up "ringleaders" of the protest.

He said authorities were taking phones and were "very aggressive" and were taking some refugees who still remain in the rooms.

World Vision Chief Advocate Tim Costello, who is on Manus Island, called on Turnbull to personally intervene and bring the unfolding humanitarian crisis "to a swift and humane resolution."

In the province as part of a delegation for the Australian Council of International Development, Costello said there is still shock on Manus among locals and humanitarian workers over Australia's decision to walk away from the centre.

"You know, 'how could they do that,'" he told the HuffPost Australia.

People here, from the top down, say with shock and grief, 'Australia just walked away.'Tim Costello

"'The overwhelming feeling is 'we're having to do something grubby for Australia, and it's their problem not ours.''"

He said the local school in Lombrum, where the centre is located, had been closed and a cordon around the facility extended, while PNG's armed "mobile squad" is on scene. Locals had kept the men in food and water after services were cut, he said.

"Whether it happens today or tomorrow... it sounds like this is now the finale and they are determined to move them," Costello said.

"Water is the crisis here. Rubbish was thrown by police in the well the refugees have dug. They're not getting enough water. "

Prime Minister Malcolm Turnbull on Thursday urged the men to move to alternative accomodation.

"They should go so peacefully and they should do so in accordance with the lawful directs of Papua New Guinea, which is the country in which the centre is located," Turnbull said.

More than 400 men remain inside the centre weeks after water, power and food was cut off. The men are refusing to move to alternative accomodation on the Island province amid fears for their safety.

Immigration minister Peter Dutton said it was "outrageous" the men were still there.

"We want people to move, and in the end it's an issue for PNG police and authorities up there," he told 2GB Radio.

"I think it's outrageous that people are still there. They've trashed the facility, they're living in squalor."

He said footage of a violent clash would not twist the government's arm to bring the men to Australia.

The Australian Federal Police are there in a "liaison" capacity, having no police powers in PNG.

But Greens senator Nick McKim said there presence confirms Dutton and Prime Minister Malcolm Turnbull have control.

"The AFP's involvement in the attack on the men in the Manus Island centre now underway confirms that Dutton and Turnbull are in charge," he tweeted.

"Call them now and demand they stop."

The developments come as prominent Australians including Rosie Batty and Ita Buttrose signed an open letter to Prime Minister Malcolm Turnbull and Opposition leader Bill Shorten urging them to address the unfolding "human disaster".

"This is not who we are as Australians or indeed as human beings," the letter says, urging Turnbull and Shorten to find safe haven for the refugees without any further delay.

"We believe that it is time to stop the unacceptable and internationally criticised treatment of the refugees on Manus island, who though innocent of any crime, have been incarcerated and now abandoned there."

The signatories include the renowned psychiatrist and Australian of the Year in 2010, Professor Patrick McGorry, who has been in touch with medical professionals currently denied access to the Manus Island detention centre.

Australian Medical association President Michael Gannon said the peak body was very concerned witht he unfolding situation.

"The AMA is uniquely placed to put together a team of doctors who have the expertise to independently verify the quality of the health care," he told the ABC.

"Professor McGorry and I are meeting later today. We plan to work together to address, to the extent we can, the serious mental health and physical health emergency that's unravelling in Manus."

More to come.