At least 30 people were injured in the flood-hit eastern Indian state of Bihar when they clashed with police as they demanded more food and clothes, witnesses and officials have reported.

Hundreds of thousands of people are hungry and homeless in South Asia's worst flooding in decades, and have complained that help is yet to reach them, while local politicians and officials have been caught stealing meagre stocks of food.

Police used batons to disperse villagers fighting for food and relief material late on Friday in Begusarai and Nalanda districts of impoverished Bihar, vast swathes of which have been inundated by the annual monsoon rains.

Hungry flood victims protested on Saturday against the police action, forcing authorities to transfer some relief officials.

"I have removed the concerned administrative officer for his uncalled for action on flood victims seeking relief," said Begusarai's top administrator, Sanjeev Hans.

Villagers from the area said there was no electricity as flood waters swamped a power station.

"We have increased supply of food and relief to reach the last stranded man," Satish Chandra Jha, a senior official, said.

At least 61 new deaths by drowning have been reported from Bihar since Thursday evening, raising the death toll in the South Asian flood to nearly 700 in the past few weeks.

KILLER DISEASES

In neighbouring Bangladesh, drowning and disease killed another 27 people overnight, officials said, taking the death toll in the floods to 253.

As floodwaters receded, the number of people suffering with flood-related diseases has increased, as outbreaks were reported from all the 40 flood-affected districts of the country, an official said.

"We are receiving an increased number of patients everyday, and last night the numbers have crossed 1,000," doctor Azharul Islam Khan said at a local hospital. "Mostly children, women and elderly people are suffering from diarrhoea."

Khan said diarrhoea could soon turn into an epidemic with officials estimating nearly 4,500 people contracting the disease during the last 24 hours.

In Pakistan, 28 people, 26 of them in the port city of Karachi, have died in rain-related accidents in southern Sindh province over the past two days, provincial health minister Syed Sardar Ahmed told Reuters.

He said eight people died of electrocution and 18 because of wall and roof collapses in Karachi.