Bangladesh's ruling Awami League is poised to win a violence-plagued parliamentary election.

The outcome was never in doubt after a boycott by the main opposition party.

With fewer than half of the 300 seats being contested, voters cast ballots in modest numbers amid heavy security.

International observers said the election was flawed.

Low voter participation could pile new pressure on Prime Minister Sheikh Hasina to find a compromise with the opposition, Bangladesh Nationalist Party (BNP), for holding new elections.

Results in constituencies that featured a contest were expected late today or early tomorrow.

Mr Hasina is expected to form a new government sometime this month.

Either Mr Hasina or BNP chief Begum Khaleda Zia has been prime minister for all but two of the past 22 years.

The two are bitter rivals.

"The immediate fallout of this dismal voter turnout will be the Hasina government coming under greater pressure to hold talks with the opposition," said Hossain Zillur Rahman, an economist and adviser to a former "caretaker" government tasked with overseeing an election.

"It is the ultimate sign of protest by Bangladeshi people and tells us that they are unhappy with the way elections have been held in this country."            

The impasse between the two main parties, which showed no sign of easing, undermined the poll's legitimacy.

It also fuelled worries of economic stagnation and further violence in the impoverished South Asian nation of 160 million.

The country's $22 billion garment industry, which accounts for 80% of exports, has been disrupted by transportation blockades ahead of the election.

BNP officials said party supporters would maintain the blockade and called another in a series of general strikes starting from tomorrow.

Eighteen people were killed in separate incidents on election day, according to media reports.

Voting was halted at more than 150 polling stations.

More than 100 people were killed in the run-up to the ballot, mostly in rural areas, and fears of violence had been expected to keep many voters away.

Police said they had been forced to fire on opposition activists in six incidents.

Apart from a handful of crude bomb explosions, Dhaka was calm.

In Satkania, near the port city of Chittagong, a poll official's arms were broken and police were attacked.