Staff from World Vision also called upon believers to pray that aid agencies and government teams might be able to prioritise the most vulnerable people affected.
Giving an update from Bangladesh, where there have been 144 deaths, Senior Director of Operations Jared Berends said the recent flooding is the worst for many years.
Speaking with Premier, he said: "We have around eight million people who are greatly affected by these floods; these are people who have lost homes and crops, and many of them are sick as a result of the foods. They're also suffering from food insecurity.
"We do have flooding here almost annually but this is a significant flood. This is much more than usual. This is a flood that happens once every ten or 20 years. It is a significant humanitarian event here."
The United Nations warned on Friday that flooding caused by severe monsoon rains during August have affected 40 million people across Bangladesh, India and Nepal.
The UN Office for the Coordination of Humanitarian Affairs said: "The floods have damaged and destroyed homes, schools, health facilities and many people are currently living in relief camps and temporary shelters.
"People are in urgent need of food, clean water and sanitation, and shelter. There is also an urgent need for health services to prevent the spread of waterborne diseases."
This is the fourth time Bangladesh has been affected by floods since January and there are fears more rain in the coming days and weeks could life for Bangladeshis worse.
Word Vision has been distributing cash to families to help them afford food and clean drinking water, as well as seeds so they can re-establish their livelihoods.
Speaking from the capital of Bangladesh, Dakar, Mr Berends said: "Our team was telling me yesterday that they could see the joy of people who were receiving these [payments]. Just a small cash grant will help them to restore their lives."
Click here to listen to Premier's Tola Mbakwe speaking with World Vision's Jared Berends: