The United Nations warned on Monday that the international community had failed to respond to the latest flooding crisis in Pakistan, leaving three million people in urgent need of food handouts.

The nuclear-armed Muslim state has suffered two consecutive years of floods but has been at increasing risk of international isolation since US troops found and killed Osama bin Laden near the capital in May.

"Somehow the present flooding and the humanitarian impact of the present flooding has not yet picked the interest, the focus of the world," said Ramiro Lopes da Silva, deputy executive director of the World Food Programme (WFP).

"If we have no resources, we have no response," he told a news conference in Islamabad after visiting the flood-hit southern province of Sindh.

On September 18, the United Nations led an appeal for $357 million in emergency funding to shore up rescue and relief efforts for millions of people suffering after floods swept away homes and farm land in southern Pakistan.

"The funding is not coming as swiftly and as fast at the levels it came to the response of the floods of last year," said Lopes da Silva.

"Donors are being challenged by the level of resources required to address similar needs of humanitarian situations across the world," he added.

Last month, the United Nations said only the Japanese government had pledged $10 million in response to the appeal.

The Pakistani government says more than 350 people have been killed and over eight million people affected this year by floods, following the 21 million hit last year in the nation's worst ever disaster.

The WFP official said three million Pakistanis were in urgent need of food security and said the UN agency would help "2.4 million of those severely affected by food insecurity".

Pakistan has been forced to fend off charges of mishandling the crisis by failing to invest in adequate measures to mitigate against seasonal rains, after last year's floods caused losses of $10 billion.

The country has faced increasingly trenchant criticism in the West for its alleged double dealings with Islamist militants opposed to Indian rule in Kashmir and fighting American troops in neighbouring Afghanistan.