One-third of Bangladesh and Nepal have been flooded, said Martin Faller, deputy regional director for Asia Pacific at the International Federation of Red Cross and Red Crescent Societies.

"This is fast becoming one of the most serious humanitarian crises this region has seen in many years and urgent action is needed to meet the growing needs of millions of people affected by these devastating floods," Faller said.

"Millions of people across Nepal, Bangladesh, and India face severe food shortages and disease caused by polluted flood waters," he added.

According to officials, more than 400 people have died in the three countries over the last seven days, with India accounting for 239 fatalities, 128 dying in Nepal, and 39 in Bangladesh.

Flood levels had already reached record heights in Bangladesh. Flooding of major rivers such as the Jamuna surpassed levels from 1988, the year of the deadliest floods the country has ever faced, the humanitarian agency said.

"More than one-third of Bangladesh and Nepal have been flooded and we fear the humanitarian crisis will get worse in the days and weeks ahead," Faller said.

In Nepal, many areas remain cut-off after the most destructive floods and landslides in recent times on August 11-12. Villagers and communities are without food, water, and electricity.

In India, 168 deaths were reported in the Bihar and Assam states, the worst-hit by the floods. Officials said the situation remains grim with the weather bureau forecasting more heavy rain in the region over the coming days.

News24