As many as 1.5 million people are being treated for illnesses related to the flooding, including diarrhea, skin disease and respiratory infections, CNN said Monday.
Acute diarrhea cases exceed 204,000 and skin diseases such as scabies have topped 263,000, a report from the World Health Organization said Sunday. Another 204,000 acute respiratory infections have also been reported.
"Strong water and sanitation interventions, such as providing clean drinking water supply and addressing environmental hazards, are urgently needed to prevent outbreaks of water-borne diseases" in Charsadda, Nowshera and Peshawar, the WHO said.
The United Nations said more than 3.5 million children could be in danger of contracting deadly diseases through contaminated water and insects.
The floods have destroyed or damaged more than 200 health facilities, New Delhi's NDTV said.
"The depth of suffering is incalculable as risks escalate of diarrhea, acute respiratory infection, malaria and other communicable diseases," WHO physician Guido Sabatinelli said. "It is crucial that all humanitarian health providers, local and national, coordinate their relief efforts closely to save lives, reduce suffering and deliver the most effective response."
The United Nations called for $460 million in aid over the next six months and International Monetary Fund officials said they would meet to discuss the economic impact of the flooding.
More than 1,600 people have died in the flooding and up to 20 million are homeless, officials said.