Record monsoon rains in south and southwest Pakistan and glacial melt in northern parts triggered the flooding that has impacted nearly 33 million people in the 220 million South Asian nation, sweeping away homes, crops, bridges, roads and livestock in damages estimated at US$30 billion.
The National Disaster Management Authority reported 1,508 deaths including 536 children and 308 women.
Hundreds of thousands of people who have been displaced are in dire need of support in term of food, shelter, clean drinking water, toilets, and medicines.
Many have been sleeping in the open by the side of elevated highways.
The torrential monsoon, which submerged huge swathes of Pakistan, was a one in a hundred-year event likely made more intense by climate change, scientists said on Thursday.