Border posts are expected to be set up on Bougainville and Solomon Islands, at the border, and those crossing in future may need visas or permits.
Papua New Guinea and Solomon Islands have just signed a border agreement and a Framework Treaty that's been a decade in the making and will govern their relations.
PNG's director-general for international relations, Jackson Yuasise, says the border agreement covers quarantine and customs matters and the movement of people.
He says at the moment there is no border post at which people crossing from, say, Solomon Islands to PNG must receive a visa or permit.
"Our intention also through that agreement [is] that the governement would set up a post on Bougainville on Buka so that when people cross over they can easily get a visa or permit."
Mr Yuasise says it is also hoped the border deal will help control the illegal movement of guns and other across a border that's seen considerable gun-running.