Bangladesh's main opposition leader and more than 100 other top party members were charged on Sunday with the murder of a policeman killed in demonstrations that have erupted ahead of upcoming elections.

"At least 164 Bangladesh Nationalist Party including Mirza Fakhrul Islam Alamgir were accused of murdering the police officer," police official Salahuddin Mia said, adding that charges had been filed against them.

Those being charged make up the bulk of the BNP leadership and potentially face up to the death penalty if they are found guilty.

Alamgir, 75, the BNP's secretary-general, has led the party since BNP chairwoman and two-time former premier Khaleda Zia was arrested and jailed, and her son went into exile in Britain.

Dhaka police commissioner Habibur Rahman had earlier said Alamgir had been "detained for interrogation" for  Saturday's violence in which a police officer and a protester were killed, and at least 26 police ambulances were torched or damaged.

Police on Saturday said the officer had been hacked to death and accused BNP activists of the killing.

The resurgent opposition has been mounting protests against the prime minister for months, despite ailing leader Zia being effectively under house arrest since her release from prison after a conviction on corruption charges.

Saturday's protests by BNP and the largest Islamist party, Jamaat-e-Islami, were among the biggest this year, and marked a new phase in their campaigning, with a general election due before the end of January. 

Protests continued on Sunday in multiple locations.

More than 100,000 supporters of the two major opposition parties rallied on Saturday to demand Prime Minister Sheikh Hasina step down to allow a free and fair vote under a neutral government.

Dhaka Metropolitan Police said at least 1,480 opposition activists had been arrested and charged with violence since 21 October. 

They include nearly 700 people arrested during Saturday's protests.