Security forces including the elite Rapid Action Battalion (RAB), the navy, border and coast guards, as well as auxiliary police units will guard some 40,000 election booths across the poor South Asian nation.
Bangladesh's communications regulator ordered the country's mobile operators to shut down 3G and 4G services until midnight on Sunday "to prevent the spread of rumours" a spokesman said.
With more than 100 million voters registered for the December 30 polls, Sunday's vote represents one of the world’s largest democratic exercises.
Prime Minister Sheikh Hasina is expected to win a record fourth term.
But the opposition says its candidates have been disqualified and supporters jailed in a pre-election crackdown
Political rallies turned violent almost as soon as campaigning began.
Thirteen people have been killed and thousands injured in skirmishes between Hasina's supporters and Bangladesh Nationalist Party (BNP) activists.
Main opposition party BNP, whose leader Khaleda Zia is serving a 17-year jail term, says more than 14,000 of its activists have been detained since the election was announced on November 8.
The BNP said over 1,100 people were rounded up on Friday alone.
The party also alleges that around 12,000 activists were injured in attacks by members of the ruling party Awami League who, in turn, denies the allegations.
The United States has raised concerns about the elections while the United Nations called for greater efforts to make the vote fair.
#BDElection18 :The US is concerned by the high level of campaign violence of last 2 weeks ahead of the upcoming polls in #Bangladesh. Ambassador (@USAmbBangladesh) noted that Opposition party candidates have owned the brunt most violence @usembassydhaka @UNHumanRights @HuffPost pic.twitter.com/g5IpdqEfk0Basherkella - বাঁশেরকেল্লা (@basherkella) 29 décembre 2018