Twenty-two people were arrested last week for alleged vote-rigging in the King's Park constituency in Yau Tsim Mong District, where a candidate won by just two votes.
These were the first prosecutions amid a row over ballot rigging that marred the district council elections on November 6.
The Independent Commission Against Corruption (ICAC) charged six of the arrested on Sunday with one count of engaging in corrupt conduct for giving false information to electoral officers. The six are registered under an apartment in Mong Kok, but all hold different surnames.
Candidate Lam Kin-man from the Association for Democracy and People's Livelihood narrowly lost his seat to independent district councillor Leung Wai-kuen.
Lam lodged a complaint to the ICAC earlier, saying he had collected 57 suspicious registrations in seven flats. He may take the issue to court to overturn the result.
Lam said he would file an election petition by January 10 at the latest.