Twenty-one people have died and five others remain missing in rain-induced disasters since incessant rain began on Thursday in Nepal, Prime Minister Balendra Shah said on Sunday.

Five others are injured and receiving treatment, Shah said on his Facebook page on Sunday evening.

The National Disaster Risk Reduction and Management Authority said in a statement that 747 families have been affected, while 143 houses had been destroyed and 51 others have been partially damaged as of Sunday evening.

"The adverse weather has disrupted transportation in several parts of the country, with more than a dozen roads affected by floods and landslides," Shah said.

Flooding has also disrupted 1,013.2 megawatts of electricity supply through the national transmission network, while hydropower projects with a combined capacity of 318 megawatts have been shut down after transmission towers collapsed, he said.

"The danger has not yet passed," Shah wrote.