The UN has made an appeal for up to $500m to help victims of Pakistan's flood disaster, which has affected at least 14m people.
So far, about 1,600 people have been killed by the monsoon floods and aid agencies have warned that many more lives will be lost unless international assistance increases substantially.
The warning comes as Pakistan has issued fresh flood warnings, putting parts of Punjab and Sindh on alert.
Pakistan's government has admitted being unable to cope with the scale of the crisis and the political opposition is compounding pressure on President Asif Ali Zardari.
President Zardari returned home this week from foreign visits.
Hardline Islamic charities have plugged some of the vacuum, leading to warnings within the US about rising extremism in a country on the frontline of the US-led war on al-Qaeda.
The Pakistani Taliban have urged the government to reject Western aid for victims of devastating floods, saying it would only be siphoned off by corrupt officials.
Against this background, the meteorological service has warned of further floods in Hyderabad district, which could spread devastation further south in Sindh province. It has issued a 'significant' flood forecast for Kalabagh and Chashma in Punjab.
More than 1,600 people have died in the floods, two million have been forced from their homes and the lives of about 14m people have been disrupted, or 8% of the population.
Floods triggered by unusually heavy monsoon rain have scoured the Indus river basin leaving a trail of destruction from mountains in the north to the plains of Sindh province in the south.
The UN says the disaster is the biggest the country had ever faced and it would cost billions of dollars to rehabilitate the victims and rebuild ruined infrastructure.
Hundreds of roads and bridges have been destroyed and waters have not yet crested in the south, meaning the situation could get worse in that region.
