The voting in the by-polls to three constituencies -- Dhaka 10, Gaibandha 3, and Bagerhat 4 -- is underway amid the fear of coronavirus outbreak.
The voting began at 9am on Saturday and will continue till 5pm without any break.
The Election Commission is holding the polls at a time when at least 20 people have been infected by Covid-19 in Bangladesh, of whom one died and three were sent home following recovery.
Covid-19, a new strain of coronavirus, has killed over 10,000 people across the world.
In Bangladesh, the government also imposed restrictions on all kinds of political, social, cultural, and religious gatherings in an effort to contain the spread of the coronavirus in the country.
The Election Commission is using Electronic Voting Machines (EVMs) in Dhaka 10 constituency, while ballot papers are being used in two other constituencies.
Meanwhile, the health officials warned that holding the election during the current situation will pose risk for users who will cast their votes via EVM.
"Using EVM system in the election will increase the risk of contamination as the system needs a finger to use it," Additional Director General of Directorate General of Health Services (DGHS) Nasima Sultana told reporters on Friday.
A total of 312,281 voters are expected to cast their votes for six aspirants in Dhaka 10 by-polls while 408,074 voters for four candidates in Gaibandha 3, and 297,434 voters for two candidates in Bagerhat 4 constituency.
However, Election Commission Senior Secretary Md Alamgir on Thursday urged voters to come to the polling booths demanding that comprehensive measures have been taken to prevent coronavirus spread.