Survivors of a landslide that entombed a village in northern Afghanistan mourned hundreds of dead relatives on Sunday as aid teams rushed to care for 700 families left homeless in the mountains.

Much of Aab Bareek village in Badakhshan province was swallowed on Friday by a fast-moving tide of mud and rock that sweep down the hillside and left almost no trace of 300 homes.

Government officials have put the current death toll at 300 people and warned it could rise by hundreds more, after initial reports suggested that as many as 2,500 people may have died.

Large crowds gathered at the remote disaster site, where the volume of deep mud covering houses made rescue efforts hopeless.

Only a few dead bodies have been pulled from the debris.

Wailing near her father's destroyed house, Begum Nisa, a 40-year-old mother of three, described the moment when the wall of mud smashed through the village.

"I was eating lunch by the window of my house, then suddenly I heard a huge roar, and I realised that our village was hit by landslides," she said.

"I shouted to my family to save themselves, but it was too late. I have lost my dear father and mother. I also lost my uncle and five members of his family."

Local people and emergency workers had used shovels to try to dig out survivors but without success, and relief work turned to caring for about 700 displaced families.

Tents, food and water began arriving on Saturday as Afghan and international aid groups worked to get supplies through to the village.

- More landslides feared -

Many families spent another night in the open, with residents and visiting officials fearing that the unstable hillside could unleash more deadly landslides in the coming days.

"We have a list of around 300 people confirmed dead," Badakhshan governor Shah Waliullah Adeeb told reporters at the scene on Saturday.

"We cannot continue the search and rescue operation anymore, as the houses are under metres of mud. We will offer prayers for the victims and make the area a mass grave."

Many villagers were at Friday prayers in two mosques when they were entombed by the torrent of mud, and a second landslide hit people who had rushed to assist those in need.

Afghanistan held a national day of mourning on Sunday after President Hamid Karzai expressed his condolences to those who had lost loved ones.

The UN mission in Afghanistan said its staff was on the ground, along with the Afghan Red Crescent and other aid groups.

"The immediate focus is on approximately 700 families displaced either directly as a result of this slide or as a precautionary measure from villages assessed to be at further risk," UNAMA said.

It added that more water, medical support, food and emergency shelters were needed.

Badakhshan is a mountainous province in northeast Afghanistan bordering Tajikistan, China and Pakistan.

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

The landslides follow recent severe flooding in other parts of northern Afghanistan, with 150 people dead and 67,000 people affected by floods in Jowzjan, Faryab and Sar-e-Pul provinces.

Flooding and landslides often occur during the spring rainy season in northern Afghanistan, with flimsy mud houses offering little protection against rising water levels and torrents of mud.

Afghanistan 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 vote on June 7.

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