Papua New Guinea's National Fisheries Authority is threatening to revoke fishing licences if Vanuatu flagged vessels refuse to acknowledge fish caught within PNG waters.
The Vanuatu Government has written to PNG informing it of a new domestic law specifying that any catch by a Vanuatu flagged ship is a product of Vanuatu.
The managing director of the PNG National Fisheries Authority, Sylvester Pokajam, says it is rejecting the new law.
"We are saying that no we won't agree with it. There's no way we'll agree with it. If you catch in your water, you catch your fish, that's your right. But if you fish in my waters, you fish under my licence and conditions. You don't fish under your licence and conditions. So the catch in our water it the catch of PNG, irrespective of flag."
Sylvester Pokajam says the PNG government has written back to Vanuatu saying it won't accept the new law.