Authorities in Nepal and neighbouring India have sent food, medical supplies and tents to areas where monsoon floods have killed at least 180 people and displaced thousands more in recent days.

Four helicopters with relief supplies and medical workers were sent on Monday to villages cut off in western Nepal, said Jhanka Nath Dhakal of the country's National Emergency Operation Centre. Most roads into the area are submerged or damaged by flooding, preventing vehicles from passing.

Thousands of people are without shelter in 10 flooded districts, and local officials on Monday distributed rice and lentils as well as cooking pots to people who lost their homes. The area is mainly farmland where the poor live in mud and straw huts that wash away easily.

At least 100 people have died in Nepal since Thursday, and at least 84 have died in India owing to torrential rains or overflowing rivers after Nepalese dams were opened, authorities said.

At least 50 people have died in Uttarakhand state, India, many of them washed away as rivers overflowed, submerging villages and fields. Officials in neighbouring Uttar Pradesh state reported a further 10 deaths overnight, pushing its toll to 34.

People in the worst-affected villages were being evacuated to relief camps set up in government and school buildings, said Alok Ranjan, a government official in Uttar Pradesh.

State authorities said soldiers were using about 400 boats to help evacuate people from their homes after entire villages were marooned in northern Uttar Pradesh.

Nepal's prime minister, Sushil Koirala, appealed to domestic and foreign agencies to help flood victims in the country. The main opposition party, the Communist party of Nepal (Maoist), disrupted parliamentary proceedings and demanded the government declare a national emergency.

Dhakal said the government was trying to send medical teams and supplies to prevent diseases such as cholera that can follow flooding. They are also distributing tents and plastic sheets to make temporary shelters, utensils to cook food and clothes for those who lost their belongings.

The June-September monsoon season often brings flooding to Nepal and India. The rains caused a landslide this month that covered an entire village near Kathmandu, killing 156 people.

Last year, more than 6,000 people were killed as floods and landslides swept through Uttarakhand during the monsoon season. Heavy deforestation over the last few decades has made the area more vulnerable to landslides.