An official says more than 500 asylum seekers remain in a decommissioned Australian immigration camp in Papua New Guinea after a court ruled authorities no longer have to supply power, food and water.

The camp inside a Manus Island navy base was declared closed on Oct. 31 based on the Papua New Guinea Supreme Court's ruling last year that Australia's policy of housing asylum seekers there was unconstitutional.

Papua New Guinea police Chief Superintendent Dominic Kakas said by Wednesday 38 asylum seekers had left the camp after the Supreme Court on Tuesday rejected an application to restore basic services on human rights grounds.

That means 54 of the 606 asylum seekers in the camp have left since the camp officially closed in October.