The IMF said it would review Pakistan's budget and economic prospects due to the magnitude of a disaster that has ravaged crops and infrastructure, left more than 4 million homeless and raised concerns that Islamist militants may exploit the chaos.

Agriculture, the mainstay of the economy, has been hit hard. The floods have destroyed or extensively damaged crops over 4.25 million acres (1.7 mln hectares) of land, including cotton, rice, sugar cane, maize, said Food Minister Nazar Muhammad Gondal.

IMF help may come in the form of lowering some of the fiscal targets of the loan program or allowing the government to abandon it and take IMF emergency funding for countries hit by natural disasters.

Mohsin Khan, former head of the IMF's Middle East and Central Asia Department, said Pakistan's IMF program should be scrapped and a new one negotiated with fresh funding of about US$6.5 billion.

Authorities have been accused of moving too slowly, and Islamist charities, some with suspected links to militant groups, have rapidly provided relief to Pakistanis, already frustrated with their leaders' track record on security, poverty and chronic power shortages.