The National Election Committee began distribution Thursday of 8 million controversial voter information cards.
The cards, which NEC officials say help people find ballot stations and encourage them to vote, will be disbursed through every province and municipality.
Critics say the cards are exploited by local officials to stifle voting by those who don't support the ruling Cambodian People's Party.
The cards are often misconstrued as a necessary document for voting, and they are withheld from non-supporters, critics say.
"Most of the people don't know what these information cards are," said Muth Chantha, spokesman of the Norodom Ranariddh Party. "Even I myself, the authorities have not come to my house to explain about the information cards."