The worst floods in memory in Pakistan have affected more than three million people so far and the death toll has climbed to over 1,500, the UN Children's Fund (Unicef) has said.
Amid forecasts of more heavy monsoon rains, authorities on Tuesday said they expected the death toll to rise further.
The Swat valley, which has yet to recover from a major Pakistani army offensive against Taliban fighters just over a year ago, is one of the areas worst affected by the floods.
Large parts of the valley's upper regions, reached by a riverside road, are inaccessible. Scores of bridges, roads and building have been washed away by the torrents.
Swat is in northwestern Pakistan, hit the hardest by the floods which submerged extensive areas, brought down bridges and swept away entire villages.
Martin Mogwanja, the Unicef representative in Pakistan, told Al Jazeera that the number of people affected continues to increase as the floods spread to the south of the country.
"This massive amount of water is moving downstream through the Punjab and Baluchistan provinces, and also moving through the Sindh province, where embankments have been broken and water is moving into to low-lying areas," Mogwanja said.
Other relief agencies such as the World Health Organisation said they were rushing in medical kits to affected areas to deal with diarrhoea.
With infrastructure crippled and drinking water sources contaminated, there are growing fears about an imminent outbreak of disease.
Aid agencies and Pakistani government officials will meet on Tuesday to determine whether to make an urgent international appeal for help.
Pakistan's National Disaster Management Authority said more than 29,500 houses were damaged and a key trade highway to China was blocked by the flooding.
"The entire infrastructure we built in the last 50 years has been destroyed," a spokesman for the provincial Disaster Management Authority in Khyber-Pakhtunkhwa said.
The floods have triggered heavy criticism of the government over its response to the disaster.
Red: Deeply affected
Yellow: Moderately affected
Brown: Flood warning issued
Around 300 people blocked a major road in the hard-hit Nowshera district to protest against receiving little or no aid, witnesses said.
Many residents who lost their homes and livelihood also say they had not received any advance warning that raging waters were heading their way.
President Asif Ali Zardari's government is already unpopular over widespread allegations of corruption and its failure to tackle politically-explosive issues such as chronic power cuts.
Zardari is currently in Europe on a state visit.
Officials said it was too early to estimate the damage the floods had caused to the economy, but the rains had so far spared the main agricultural heartland in the Punjab.