Crowds of outsiders have rushed to the remote Afghan village that was buried in a landslide to try to pick up aid supplies meant for survivors of the disaster, the United Nations said Wednesday.

Much of Aab Bareek in Badakhshan province was engulfed by a fast-moving tide of mud and rock that swept down onto the village last Friday, leaving almost no trace of 300 homes.

A major international aid effort swung into action, with government officials saying the death toll was at least 300 and some estimates putting it as high as 2,500.

But the UN Office for the Coordination of Humanitarian Affairs said that the sudden arrival of food, tents, blankets and medical supplies had attracted many locals from surrounding parts of the mountainous northern province.

"Access challenges at the site are now impeding the assessment of needs and the delivery of assistance, as more and more people from outside the immediate community are congregating at the disaster site," the UN warned.

"Aid agencies are increasingly challenged to distinguish between those directly affected by the disaster and those who have come from outside the village, attracted by the quantity of relief items arriving."

Local people and emergency workers had used shovels to try to dig out anyone trapped alive after the landslide, but only a few bodies were pulled from the deep layer of mud.

President Hamid Karzai visited the site on Wednesday and vowed that new houses would be built for survivors as frustration grew over the government's response and the aid operation.

"The President visited the people in tents who were relocated from Aab Bareek village," a statement from the palace said.

"(He) assured them that there was enough national and international relief assistance to distribute to the affected.

"The President also pledged that for those who have lost their homes in the natural disaster, new homes will be built."

Badakhshan is a poor, northeastern province bordering Tajikistan, China and Pakistan.

It has been relatively peaceful since the US-led military intervention in Afghanistan began in 2001, but has seen increasing Taliban activity in recent years.

The country is in the middle of presidential elections, with former foreign minister Abdullah Abdullah and ex-World Bank economist Ashraf Ghani due to compete in a head-to-head run-off vote next month.

Both candidates have called for urgent action to support those hit by the landslide.