The Bangladesh Nationalist Party (BNP) official was attacked by supporters from the main opposition Awami League in the southern region of Bagerhat, police office Bahadur Sharif said.
"He was hacked repeatedly with machetes and died on the spot," Sharif said.
Seven others were killed on Saturday as thousands of supporters of the opposition parties and the ruling BNP went on the rampage, clashing with police in the capital and elsewhere.
Four others died on Friday and more than 100 were injured in similar clashes.
More than 15,000 police were deployed on the streets of Dhaka on Saturday as tensions rose after the government's five-year mandate expired midnight on Friday.
In the latest violence on Saturday, one person was knifed to death in the capital and two others died after they were hit with rocks. Another person was also killed although the circumstances were still unclear, officials said.
The private UNB news agency said at least 2,000 people had been injured on Saturday in running battles in Dhaka that forced police to fire tear gas to disperse demonstrators and try to restore order.
Around 100 police officers were also injured, police said.
"There were injuries on both sides. Police fired tear gas to bring the situation under control," deputy police commissioner Aurangeb Mahbub told AFP.
The violence came as Prime Minister Khaleda Zia's BNP-led coalition government prepared to hand power to an interim administration that will oversee elections within 90 days.
The government's term expired at midnight on Friday but it has 15 days to transfer authority.
The opposition had earlier vowed to paralyse the country with protests if the government installed former Supreme Court justice K.M. Hasan as the head of the interim administration.
The opposition accused him of being partisan and said fair polls would be impossible with him in the post. Hasan held a senior BNP appointment in the late 1970s.
He declined the post late on Saturday and the government has not yet announced who it intends to replace him with.
Earlier on Saturday, one man died of bullet wounds at the Dhaka medical college hospital, said a doctor, Mojammel Hoque, adding that he was unable to give further details.
A local BNP leader and his brother were shot dead after being attacked by opposition supporters in central Narsinghdi district, said police chief Mir Rezaul Alam said.

Copyright AFP (Agence France-Presse), 2006