The decision was made as joint operations are being conducted in the area against the KNF, the Election Commission said
District Returning Officer Sarowar Morshed Chowdhury said Shamsuddin Pradhan, 65, was hacked near the Baluakandi Dr Abdul Gaffar School and College on Sunday noon.
Supporters of ruling Awami League-endorsed chairman aspirant Amirul Islam and rebel candidate Refaet Ullah Khan Tota clashed during the voting.
Seriously injured Pradhan was rushed to the Gazaria health complex where doctors declared him dead.
Locals say Pradhan was working for Islam.
Pradhan was the Baluakandi unit Awami League chief and also the Union Parishad chairman.