A former Nauru justice minister says the government has amended electoral laws which further undermine democracy on the island.
Mathew Batsiua, who is one of five opposition members suspended from parliament for nearly two years, said changes would make it harder for many people to stand.
Nauru is required to hold elections by the middle of the year.
In February the government, which now dominates parliament having suspended most of the opposition, ruled that public servants wanting to stand had to resign three months before the poll.
Mr Batsiua said that yesterday the government hiked candidacy fees 20-fold, from $US74 to $US1500, and dramatically increased charges for voters wanting to move electorates.
"Those increases in fees are further attacks on the rights of people to stand as candidates. We believe it is another evidence of this government trying to rig the outcome of future elections in Nauru so they can retain their seats, and they are going out of their way to make it difficult for others to challenge their incumbency."
Requests to the Nauru government for an explanation of the changes have gone unanswered.