Police said on Saturday some 60 Bangladeshi fishing boats capsized on Friday night off Barisal coast.
"Seven bodies have been retrieved from the rough seas by boats which managed to return to the shore but more than 200 crew on board... nearly 60 boats are still missing," one police officer said.
Officials fear most of the missing would be dead by now as rainstorms that are battering South Asia continued to hit the offshore areas.
The bad weather is hampering search operations, officials said.
Storms affect Pakistan
The heavy rains are also threatening thousands of people in Pakistan's southern Sindh province where the army has been called in to help in rescue operations.
Sindh government spokesman Salahuddin Haider said on Saturday hundreds of army personnel and civil administration officials are busy rescuing people caught up in the low-lying areas of Badin.
Badin is some 300 kilometres east of Karachi where a state of emergency in all of the city's hospitals has been declared by the government.
"At least 37 people were killed in the past three days, including 10 in Karachi and five in Badin. Most of the deaths were caused by collapsing roofs, flooding and electrocution," Haider said.
Chaos in India
There were also casualties in the Indian province of Bihar.
Officials said at least 34 people have died and nearly 1.8 million people have been affected in the past two weeks.
"The floods have hit 14 of the 38 districts of the state. So far we have recorded 34 deaths and people of 1,832 villages have been fully or partially displaced from their homes,” provincial relief commissioner, Sishir Sinha said.
Officials feared the floods could worsen further following heavy rains in the past few days. Many rivers cutting through the state were flowing over danger levels.
About 1000 boats have been deployed to distribute food and medicine to those marooned.
The economic loss is expected to be huge. Bihar is one of the poorest Indian provinces, gripped by hunger and under-development.
The annual June to September southwest monsoon showers are a lifeline for the economies of South Asia.
But resultant floods also displace millions every year and result in thousands of deaths.