Pakistan needs more than $10 billion to repair and rebuild infrastructure, Planning Minister Ahsan Iqbal said on Tuesday.
"Massive damage has been caused to infrastructure – especially in the areas of telecommunications, roads, agriculture and livelihoods," he told AFP news agency.
Floods have swamped a third of the country, killing more than 1,100 people and affecting tens of millions more.
In the northwestern town of Nowshera, a technical college was turned into a shelter for up to 2,500 flood victims, who sweltered in the summer heat with sporadic food aid and little access to water for bathing.
"We have been only eating rice for the past three days," 60-year-old Malang Jan told AFP.
"I never thought that one day we will have to live like this. We have lost our heaven and are now forced to live a miserable life."
Jan's family were rescued by boat when his home was submerged in the floods.
'A situation of panic'
The college gardens are lined with tents – the classrooms are filled with the families who arrived first and grabbed the chance for privacy.
Others rest shoulder-to-shoulder in corridors with their meagre bundles of belongings.
Goats and chickens salvaged from the rising water graze in the campus courtyard.
The camp of 2,500 is managed by various charities, political parties and administrative officials overwhelmed by the scale of the disaster.
Volunteers hand out tents, mattresses, water, daal and naan.
"It's a situation of panic," said Mushfiq ur Rehman, a district court official who stepped in to oversee food delivery for the local administration.
"There is enough food, but people are getting desperate because they don't trust if they will get a meal again or not."
It is particularly difficult for women in this deeply conservative region of the country, where the all-covering burqa is commonly worn, and women rarely mix with men who are not relatives.
"We are Pashtun people; we don't come out of our homes often, but now we are forced to come out," said Yasmin Shah, 56, who is sheltered in a classroom with her family.
Young women with burqas pulled up over their heads watch from upper floors.
"I cannot come out of this classroom unless I have to," added another, looking after a blind uncle.
Older women take their place in queues to ensure they get a share of food handouts.
The heat is worsened when the few working fans stop working because of power cuts. There are no showers and only a few toilets available for the displaced.
"Our self respect is at stake... I stink but there is no place to take a shower," said Fazal e Malik, who is staying with seven family members in a tent.
"Our women are also facing problems and they too feel humiliated."
When food aid arrives at the college, desperate families mob the trucks, and are sometimes pushed back by police armed with long sticks.
"People send relief goods here but the distribution is not well organised at all," Yasmin said.
"There are routine scuffles and people have to fight to get some food. In the end, some people have a bigger share and others have nothing."
The largest camp in the town was set up at the Pakistan Air Force academy centre, sheltering a further 3,000 people in the accommodation usually reserved for training staff.
Nearby, armed members of a local political party have stepped in to protect abandoned homes, using rowing boats to navigate the flooded streets and watch for looters.
For some fleeing the deluge across the country, the only dry areas are elevated roads and railroad tracks, alongside which tens of thousands of poor rural folk have taken shelter with their livestock.