A landslide triggered by heavy rainfall has buried six villages in Nepal's mountainous northeast and at least 15 people are believed to have been killed.

Government administrator Surendra Bhattarai says the landslide hit the villages in Taplejung district at night when people were at home sleeping.

He says another 12 people are believed to be missing but details are sketchy because of the remoteness of the area. It takes several hours on mountain trails to reach the villages.

Landslides are common in mountainous Nepal during the rainy monsoon season, which began in June and ends in September.

The Himalayan nation is still recovering from earthquakes in April and May that killed more than 8,700 people and caused massive damage.