The Bougainville South MP, Tim Masiu, says the four month delay to the Bougainville referendum was not unexpected.
Bougainville is due to hold a vote on whether to become fully independent of Papua New Guinea.
It was tentatively set for June 15th this year but has now been moved, with voting to start on October 12th.
Mr Masiu, who is also PNG's deputy opposition leader, told Don Wiseman he was at Friday's Joint Supervisory Body meeting on Port Moresby when the decision was made.