FOREIGN aid began flowing on Wednesday to the 20 million victims of Pakistan’s catastrophic floods, but many remained without food or shelter as Islamabad responded slowly to their needs.

Weather forecasts signalled some respite was due with monsoon systems weakening after three weeks of torrential rains brought devastating floods that left at least 1400 people dead in the country’s worst natural disaster.

The floods have wiped out villages, farmland and infrastructure and OCHA, the UN’s aid coordination body, said today that more than 650,000 homeless families remained without basic shelter.

The United Nations last week launched an immediate appeal for $US460 million ($A508.06 million), and said on Wednesday that funding had reached 54.5 per cent of this target, though that included pledges that were yet to turn into cash.

Zamir Akram, Pakistan’s ambassador to the UN in Geneva, said the country had received more immediate multilateral relief aid through the UN and direct bilateral aid totalling about $US301 million ($A332.45 million).

The World Bank has also agreed to lend Islamabad $US900 million ($A994.04 million), warning that the disaster’s impact on the economy was expected to be “huge” and take years to put right.

Nations ranging from Afghanistan and Turkey to the US and Saudi Arabia have pledged millions in cash and relief as the UN warned more money was needed to stave off a “second wave of death” from disease and food shortages.

Britain, which is emerging from a diplomatic row with Pakistan, branded the aid effort “lamentable” and charities said Pakistan was suffering from an “image deficit” partly because of perceived links to terror.

The European Union announced today that it would provide an additional 30 million euros ($A42.7 million) in emergency relief assistance to Pakistan, bringing its total aid to 70 million euros.

The nuclear-armed country is on the front line of the US-led fight against al-Qaeda, where the military is locked in battle with Taliban in the northwest on the border with Afghanistan.

Pakistan Foreign Minister Shah Mehmood Qureshi has also warned that the disaster could play into the hands of insurgents.

Embattled President Asif Ali Zardari visited Russia on Wednesday for a regional security summit with Afghan leader Hamid Karzai and Russian President Dmitry Medvedev.

He was expected to stay in the Black Sea resort of Sochi for only a few hours, after facing heavy criticism at home for failing to cut short a visit to Europe to tackle the crisis.

“We don’t know what impact it’s having on the insurgents … the idea that this flood would essentially come on top of a very corrosive insurgency is extremely worrisome,” said US ambassador to Islamabad, Anne Patterson.

OCHA said it feared that Pakistan was on the brink of a “second wave of death” unless more funds materialised, with up to 3.5 million children at risk from water-borne diseases.

In the hard-hit Punjab, army officials said today that rescue efforts would take another two weeks before recovery and reconstruction phases of relief could begin.