The Bougainville Referendum Commission, or BRC, is not able to extend the enrolment period for people to vote in a referendum on independence from Papua New Guinea.
Enrolment ends on Sunday and the BRC is constrained by rules laid down by the governments and cannot move on this date.
Bougainville women's MP, Francesca Semoso, said there is a need to extend the period by at least two weeks, but the chief electoral officer Mauricio Claudio, said there is literally no more time for what he calls 'phase two' or the active enrolment of voters.
He said a key factor is that the writs must be issued on 16 August ahead of the referendum vote starting on 12 October.
Mr Claudio said only the two governments have any authority to change the dates.
He said the governments were late establishing the BRC and its work has subsequently been hampered by a lack of time and funding.
But Mr Claudio assures there will be a third phase when the rolls will be displayed for everyone to check they are on it and if they are not they will then be able to enrol.
But he stresses that this phase can only run for a seven-day period.