Aid workers struggled to deliver supplies to some of the 28 million people displaced across India, Bangladesh and Nepal by the worst monsoon-triggered flooding in decades, with some areas unreachable due to the high waters.

In India's Bihar state, 12 million people have seen their homes and farmland partially or totally submerged after the worst flooding in 30 years.

An overcrowded boat -- one of scores ferrying the marooned to safety -- capsized late Monday in the impoverished state, claiming the lives of at least 65 people, police told AFP.

Six women drowned in a separate boat accident, the Press Trust of India news agency reported.

Some villagers and officials reported that boat owners were only rescuing those who paid, with the going rate about 40 rupees (one dollar) a head.

"We had just enough money to pay for myself and our children and so we had to leave behind my husband," said an angry Khusboo Paswan, from Samastipur district, 150km north of the state capital Patna.

She was later reunited with her husband Mohan after volunteers rescued him and brought him to a highway junction that is now home to thousands of people forced from their homes by the floods.

Parts of Uttar Pradesh, Orissa and Assam states were also submerged during the rains, affecting another 6.5 million people, although officials said the situation had improved in Assam.

India's national disaster management agency said 1,294 people had died of monsoon-related causes from June 1 to Monday.

But figures given by state officials in Uttar Pradesh and numerous boat accidents in Bihar late Monday brought the toll close to 1,500.