Forty million people across Bangladesh, India and Nepal have been affected and 1,200 people have died. With crops destroyed, there's concern for how farmers and their families will manage.
Ram Kishan is from Christian Aid and has been working with emergency relief in Bihar, which is one of India's state worst hit by the disaster.
He told Premier the flood has been devastating and intermittent rain has made matters worse.
"Particularly there are 32 million people that are affected," he said.
"Those who are affected are faced with the challenges of meeting the food needs and meeting needs for shelter.
"There are emerging needs for water and sanitation. We do not have access to clean water. We do not have access to sanitation facilities."
Kishan said it was disheartening to see children living without protection and support as rain flooded into fields and villages.
He told Premier: "After 1988, this is the worst flood. Many, especially the young generation, haven't seen a flood in several years.
"This was an unexpected flood. People were taken by surprise and that's one of the reasons why the devastation has been much higher."
Kishan said India's government has said it can't handle the effects of the monsoon and has asked the international community to help in anyway it can.
Christian Aid has launched an emergency appeal to help those in need get food, shelter and medical help to fend off disease and start to rebuild their lives.
Listen to Ram Kishan speaking with Premier's Alex Williams here: