Members of a sectarian cult are hindering the movement of emergency supplies to flood-affected people in Papua New Guinea.

Torrential rains last month left 200 dead and thousands homeless in Oro province north of Port Moresby.

The area has long been associated with cult movements.

Anglican Church Bishop Joseph Barnes says members of a cargo cult stole relief supplies.

He says they claimed the cargo had been sent there by their dead ancestors.

"There has been interference with relief supplies being sent there by the sect group," he said.

Police are investigating.