BP Yadav, a spokesman for India's meteorological department, said the pattern of the annual monsoon had been unusual this year, leading to heavier than normal rain. "We've been getting constant rainfall in these areas for nearly 20 days, " he said.

He was referring specifically to the states of Assam, Bihar and Uttar Pradesh, which have suffered the worst of India's flooding, and where the majority of the country's 178 known fatalities occurred.

In Lucknow, the capital of Uttar Pradesh, officials said at least 12 people, mostly women and children, had died in the past 24 hours. At least 500 villages in the state are under water.

In Assam, at least 100,000 displaced people have been forced into government relief camps.

Santosh Mishra, a villager from Uttar Pradesh's Gonda district, told the Associated Press: "I have not seen such flooding in the last 24 years. There are no signs of houses, temples or trees."

In Bihar, reports said that a number of pregnant women lost their babies as flooding led to the collapse of the impoverished state's rural medical infrastructure in many areas.

"There is little one can do as nearly half of the 315 health centres in remote districts have been swamped, " said a health official.

In Bangladesh, where most of the country straddles the delta of the River Ganges, more than five million have been displaced and at least 64 killed by the flooding in recent days. Many of the people forced from their homes in search of higher ground have been carrying with them the tin walls and roofs of their houses, so that they can rebuild once the flood waters recede.

Despite the problems encountered by Bangladesh, the News Today newspaper reported that Tapan Chowdhury, the government's disaster management advisor, had said the country was not, at this stage, seeking international help. "We've adequate relief goods for distribution, " he said. "We are trying to face the situation jointly with our own strength and resources."

In Nepal, at least 750,000 people have been affected by the torrential rains which have resulted in fatal landslides and floods in the Himalayan nation's low-lying Terai region.

Some reports suggest the weather is not improving, and stocks of food and clean water are said to be running low. The World Food Programme has appealed for help to feed 60,000.

A statement issued by the Kathmandu office of the United Nations Office for the Coordination of Humanitarian Affairs said: "Food, portable water and temporary shelter [have been] identified as major needs.

Health issues have also been of particular concern in at least five districts, with reports of fever, acute respiratory infections, diarrhoea, vector-borne diseases and snake bites."

The annual monsoon rains that stretch from June to September are a double-edged sword. They replenish water supplies after southern Asia's long, hot summers, but often bring chaos and misery, usually to the region's poorest. Last year, at least 1,000 died.

Even in big cities such as Delhi and Mumbai, the rains cause havoc, and every year there are claims that the authorities have not done enough to prepare for the flooding. In Delhi, authorities were widely condemned after large parts of the capital were brought to a standstill on Thursday.

Food, water and sanitation the main problems

DEVASTATING floods have displaced up to 20 million people in South Asia. It has now been raining in northern India, Bangladesh and Nepal for more than 20 days. Irish aid agency, Concern, is working round the clock in Bangladesh to help those affected.

In Bangladesh, the water levels of major rivers rose earlier this week. Villages have been cut off. Crops have been damaged.

People are taking shelter on roadsides and do not have drinking water, shelter, sanitation facilities, cooking facilities or access to food.

Concern is using eight boats to conduct search and rescue missions in all of the flooded areas. The agency has started distributing dry food to 11,000 affected people.

The initial assessments of the flood damage identified the main priorities as food, drinking water and sanitation. Concern is looking to distribute food for up to three or four days to those families forced from their homes.

Due to the scarcity of clean water, Concern will also be supplying pure drinking water or distributing water purification tablets to the areas affected most.

It is predicted that the flooding could get worse, resulting in a greater number of affected and displaced people.

Concern is continuing to assess the situation across the country.