Papua New Guinea's Inter-Government Relations minister, Sir Peter Barter, says police have issued a warrant for the arrest of two foreigners who entered the country illegally last week.
He says the two were passengers on a Cessna Citation jet that landed without permission at Bougainville's Aropa airport.
Sir Peter says the plane had landed illegally at the disused airport several times before it was caught.
He says the two, Australian Jeff Richards, and a Briton, James Nessbit, are thought to be with the rebel Mekemui group on the island.
Sir Peter says the men had claimed they wanted to provide millions of dollars for humanitarian aid on Bougainville.
"I just don't understand how two people could think they can enter a country without going through the recognised government, and assume they can get away with what they've got away with. Their promises have been outrages, the expectations that its created, the false impressions they've left on the minds of people up there, its gonna make it that much more difficult to be able to pursue the end objective of being able to give full peace and freedom."
The pilot and the plane's owner have both surrendered to police.