Papua New Guinea has opened a detention facility in Port Moresby, annexed to the Bomana prison, to house Manus Island inmates.
Ian Rintoul of the Australia Refugee Action Coalition said the detention centre has been built with Australian money and input.
He said around 50 asylum seekers were transferred to the new detention facility on Sunday.
Mr Rintoul said they had been moved to Port Moresby under the guise of a need to repair the Hillside camp on Manus but he said this was clearly a ruse to get them to the capital city.
He said most of those moved have not been given refugee status.
"Most of them are Iranian but there is also a very large number, about 40 who are deemed to be negative but actually have never had a refugee assessment in Papua New Guinea because they said they had sought asylum in Australia and had never sought asylum in Papua New Guinea."