Islamabad: Celebrations of Pakistan`s independence on Saturday were cancelled as floods continued to bring misery to millions and the United Nations confirmed at least one case of cholera.
UN chief Ban Ki-moon was expected to arrive in the country as aid agencies warned of a "second wave" of deaths from disease.
"There has been at least one cholera confirmed case in Mingora," Maurizio Giuliano, spokesman for the UN Office for Humanitarian Affairs, told a news agency, referring to the main town in the northwestern district of Swat.
Giuliano said at least 36,000 people were reportedly suffering from acute watery diarrhoea.
"We`re not suggesting that everyone who has acute watery diarrhoea has cholera, but cholera is certainly a concern and that`s why we`re stepping up our efforts to treat cholera," he said.
Charities said relief for those affected by the worst natural disaster in Pakistan`s history was lagging far behind what was needed.
"There are millions of people needing food, clean water and medical care and they need it right now," said Jacques de Maio, head of operations for South Asia at the International Committee of the Red Cross.
"Clearly at this point in time the overall relief effort cannot keep pace with the overall scale of the emergency." he said.
Humanitarian agencies in Pakistan were keeping a close watch on the risk of "a second wave of deaths induced by the floods in the shape of water-borne diseases," de Maio added.
Celebrations of the Saturday anniversary of Pakistan`s 1947 independence from British colonial rule have been scrapped by President Asif Ali Zardari, his spokesman announced.
The embattled leader has come under fire from flood victims and the opposition after pressing on with a trip to Europe last week, despite the mounting emergency at home.
"The president has decided that he will hold no celebrations in the presidency," Zardari`s spokesman, Farhatullah Babar, told a news agency.
In his independence day message, the President will call on people "to come out and help your grief-stricken brethren," Babar said.
Zardari will also visit flood-affected areas in the northwest and the central province of Punjab.
On Thursday, he visited a hard-hit area in the southern province of Sindh and met survivors for the first time, two weeks after the floods began.
The United Nations believes 1,600 people have died in the disaster, while Islamabad has confirmed 1,343 deaths.
The UN has appealed for 460 million dollars to deal with the immediate aftermath of the floods, but charities say even this figure falls far short of what is needed.
The ICRC gave warning of the unsounded scale of the disaster, directly or indirectly affecting an estimated 15 million to 20 million people according to Pakistan.
"We have to acknowledge our ignorance and the impossibility at this point to measure with precision the full magnitude and scope... of this catastrophe," de Maio said.
UN officials warn that the damage to infrastructure and the economy will put this volatile country back years.
Up to two million people require emergency shelter and six million depend on humanitarian assistance to survive, fanning widespread anger against the weak US-backed government, amid looting and misery on the ground.
The UN`s Ban arrives late on Saturday. He "will discuss relief efforts with government leaders on Sunday and visit flood-devastated areas the same day," foreign ministry spokesman Abdul Basit told the newswire.
Outside the city of Sukkur in Sindh, residents waded through stagnant flood waters up to their chests, retrieving valuables and lashing out at the government for failing to stop looting.
"We left with our belongings in a tractor when armed men surrounded us. They snatched everything and fled," Mai Meema, 60, told AFP in a tent city.
"We were poor people but never slept on an empty stomach," she said. "This flood has made us beggars. We have nothing at all."