A Bangladesh war crimes tribunal has sentenced top Islamic party leader and secretary general of the Jamaat-e-Islami party, Ali Ahsan Mohammad Mojaheed, to death for war crimes.

Lawyers say the 65-year-old was convicted on charges of genocide, conspiracy in killing intellectuals, torture and abduction during the country's 1971 war to break away from Pakistan.

The verdict is the second this week by the tribunal after the party's 90-year-old spiritual leader Ghulam Azam was convicted and sentenced to prison for masterminding atrocities during the war.

Mojaheed was an influential minister in the 2001-06 government headed by current opposition leader Khaleda Zia.

Jamaat-e-Islami is the largest Islamic party in the country and a key opposition member.

Islamist protestors set fires in the streets during clashes with police in Dhaka in May. ( AFP: Munir uz Zaman )

The opposition in Bangladesh has criticised the cases as politically motivated and says they are aimed at settling old scores and not justice.

The government, however, says the trials are necessary to heal the wounds of the 1971 war in which it says 3 million people died. Independent estimates say the death toll lies somewhere between 300,000 and 500,000.

The UN does not endorse the Bangladesh tribunal unlike other war crimes courts.

New York-based Human Rights Watch says its procedures do not meet international standards.

Party supporters continue to clash with security forces across the country.

ABC/wires