A member of the Papua New Guinea government says Bougainville has not received all its funding because it has not spent what money it did get properly.
The Bougainville president John Momis has criticised the Peter O'Neill government for years for failing to send the funding Bougainville is entitled to.
He said the money was critical to prepare the region for its vote on continuing autonomy or independence due later this year, and to help develop its economy.
But the Bougainville Regional MP, Joe Lera, said Bougainville had spent what money Port Moresby did send, on activities that the funding was not intended for.
"The fact is in the last 15 years ABG, [Autonomous Bougainville Government], has never acquitted the money that national government was giving them," he said.
"And that is the reason why the national government does not give them the money they ask for, because there is nothing to show for the billions that they were given since the peace agreement."