Upendra Purush Timilsena, a regional police inspector, said the mudslides were caused by heavy monsoon rains that hit the village of Khaptad on Sunday
He said details were scarce because the area in western Nepal is a five-hour walk to the nearest telephone. He said about 80 houses were washed away.
Narendra Raj Sharma, the chief administrator of the district, said 10 villages along the Rapti river were also flooded and several houses washed away.
At least six people were killed in the flooding on Sunday and hundreds more were out of contact, said Sharma.
"We are still trying to acquire details on the losses," he said.
Sharma said a rescue team sent had failed to reach the area and the first contact was made only on Monday morning when a helicopter was sent.
"We have requested the home ministry to send some rubber boats and other rescue equipment," he said.
Every year monsoon rain kills hundreds of people across South Asia, with people drowning in floods, being crushed by landslides or collapsed houses, or getting electrocuted.