Farhan Haq, deputy spokesman for the UN secretary-general, said in the World Food Programme's relief efforts, an innovative project, which uses weather forecasts to trigger early actions such as cash transfers, is being used for the first time.
He said some 5,000 households, or 25,000 of the most vulnerable people, have received money through mobile transfers as part of the project.
The WFP is working with the government of Bangladesh to help more than 275,000 people affected by flooding in the country's northwest, he said.
More than 2 million people have been affected in nearly one third of Bangladesh's 64 districts, according to the government of Bangladesh.
UN humanitarian partners reported earlier that at least 30 people had been killed by monsoon rain-triggered landslides and flooding in parts of Bangladesh.