Intense monsoon rains, typhoons and tropical storms have flooded more than 2.5 million hectares of cropland in Cambodia, Laos, the Philippines, Thailand and Vietnam, according to research by the Food and Agriculture Organization.
Meanwhile, millions of animals have already been killed and millions are thought to be at risk from the flood waters and already over spilling dams.
In worst-hit Thailand, 1.6 million hectares – 12.5% of the area under crops nationwide – has been flooded, along with an estimated 12% of area in the Philippines and 7.5% of plantings in Cambodia.
"Loss of livestock and poultry is reported and significant numbers are considered to be at risk," FAO said.