Singer Shafin Ahmed, Jatiya Party's mayoral candidate for Dhaka North City Corporation (DNCC) by-polls, has alleged there have been irregularities in the vote.
He voiced the allegations on Thursday.
However, he did not specify what sort of irregularities were taking place, saying he will talk about it later.
Shafin cast his vote at Manarat International School center in the city's Gulshan area around 12:20pm.
"I cast my vote here at Manarat School. Before that, I visited some polling centers. The election atmosphere at this center is fine as I have not seen any irregularities. However, I found some irregularities at other centers I visited," he told reporters.
The opposition candidate also said they have collected some evidence of voting irregularities.
"Still, I want to see the rest of the voting time, and I'll visit some more polling centers."
The singer said he will come up with a comprehensive reaction once the voting is over.
Replying to a question whether he is hopeful about his victory, Shafin said: "I should not voice my frustration or success right now as there is still a long way to go.
Due to the rain in the morning, people were not here earlier but are now starting to come in to vote. Let us see what happens in the remaining time."
About the low turnout of voters, he said people have lost their interest in voting due to irregularities in the previous elections. "Voters might be thinking their votes have no value and that's why they are not coming to polling stations," he said.
Earlier in the day, Awami League mayoral candidate Atiqul Islam cast his vote at Nawab Habibullah Model School and College polling center in city's Uttara area.
Voting in the by-polls to the mayoral post of the DNCC plus in 36 wards of Dhaka north and south city corporations began, at 8am, amid rain and will continue until 4 pm, without a break.
The voter turnout was poor in the morning due to the rain since early Thursday.
Five candidates are vying for the mayoral post, while 116 contenders for 18 general councilor posts and 45 aspirants for six reserved seats which are exclusively for women. Of them, one general councillor candidate was elected unopposed in the city.
The five mayoral candidates are: Awami League's Atiqul Islam (Boat), Jatiya Party's Shafin Ahmed (Plough), NPP's Anisur Rahman (Mango), PDP's Shahin Khan (Tiger), and independent runner Abdur Rahim (Table Clock).
