Army soldiers patrol outside the state secretariat in Dhaka on Saturday. AFP

Bangladesh holds a general election on Sunday, with Prime Minister Sheikh Hasina set to win a fourth straight term and the fifth overall for her Awami League-led alliance, despite an economy that required an international bailout last year.

Here are key facts about the election in the South Asian country of almost 170 million people:

• The main opposition Bangladesh Nationalist Party of the ailing former Prime Minister Khaleda Zia is boycotting the poll after Hasina denied its demand to resign and let a caretaker government run the election.

• Violence erupted on the eve of the election, with a passenger train fire, which officials called arson, killing at least four people and several polling booths set ablaze around the country.

• Women make up almost half of the nearly 120 million eligible voters, while first-time voters number about 15 million.

• Nearly 2,000 candidates overall are vying for the 300 directly elected parliament seats, with a record high 5.1% women candidates.

• There are 436 independent candidates in the race, the most since 2001. The BNP says the Awami League has propped up "dummy" candidates to try to make the election look credible, a claim the ruling party denies.

• Hasina has been credited with turning around the $416-billion economy and its massive garments industry, while also winning international praise for sheltering nearly a million Rohingya Muslims fleeing persecution in neighbouring Myanmar.

• But in recent months, the economy, once among the world's fastest-growing, was rocked by violent protests after a jump in the cost of living, as Bangladesh struggles to pay for costly energy imports amid depleting dollar reserves and a domestic currency.

• The International Monetary Fund cleared the first review of Bangladesh's $4.7 billion bailout in December, providing immediate access to $468.3 million and made $221.5 million available for its climate change agenda.

• Rights groups have accused the government of targeting opposition leaders and supporters, while Hasina and the Awami League have repeatedly condemned the BNP as troublemakers set on sabotaging the elections.

• Nearly 800,000 police, paramilitary and police auxiliaries will guard the polls on election day. Officials of the army, navy and air force have also been deployed.

•  As many as 127 foreign observers will track the election process to assess its fairness, while 59 journalists from abroad have been accredited.

• The top buyer of Bangladeshi garments, the United States, warned in May that it would restrict visas for Bangladesh citizens who undermine the democratic election process.

• Voting begins at 8 am (0200 GMT) and ends at 4pm (1000 GMT). Counting will start soon after the end of voting, with initial results expected by Monday.

Reuters