Asylum seekers who have had their claims and appeals rejected on Manus Island have been told to prepare for deportation.

Anyone found to be stateless will remain at the Australian-funded detention centre or be transferred to "any location, including correctional institutions".

In documents obtained by the ABC, Papua New Guinea Immigration told the so-called "double negatives" they have no option of remaining in PNG and will never go to Australia.

The document said "Immigration and Citizenship Services (ICSA) has scheduled an interview with you to plan for your departure from PNG ... you must depart from PNG as soon as practicable".

An asylum seeker inside the centre said the notice applies to about 50 people with "double negative" status, with a further 120 men waiting for the result of their appeal.

They have been being offered money if they return voluntarily with the International Organisation for Migration.

"If you are involuntarily removed you will receive no financial assistance," the document said.

Asylum seekers were informed of the imminent deportations last week but it is not clear if actions have yet been taken.

The rejected asylum seekers were told a final interview "in the next 1-2 days" will give them one last chance for fresh information about their case and will consider any reason their return would breach PNG's international legal obligations.

"If ICSA assesses that you cannot be removed to your country of origin, you will remain in custody until you are able to obtain a visa to lawfully enter and reside in PNG or another country," it said.

"You will continue to be accommodated at the Regional Processing Centre. However you may be held in any location, including correctional institutions, while your removal is being effected."

Unclear how asylum seekers will get legal representation

Asylum seekers have been told they have the right to have a PNG-certified lawyer present at the interviews, but it is not clear how the men would arrange such representation.

"If the lawyer charges a fee, this must be paid by you," the PNG Immigration documents said.

There is only one lawyer permanently based on Manus Island.

The developments inside the detention centre have taken place at a time of controversy outside the Australian-run facility.

On Wednesday the Manus Island police commander threatened to arrest management for their role in helping three expatriate security guards leave the island following an alleged rape incident in mid-July.

The following day two charter planes evacuated some staff from the Regional Processing Centre.

Asylum seekers say they are afraid of expatriate guards and also fear possible reprisals from the family of the young woman involved.

In recent days, 10 to 20 unarmed PNG Navy personnel have been brought in to bolster each security shift at the facility, which is located on an isolated navy base on the remote island.

The Rudd government changed immigration policy in July 2013 to send all male post-July 9 boat arrivals to Manus Island, but to date no refugees have been resettled in Papua New Guinea.