Kathmandu: Several people were missing in eastern Nepal on Wednesday after villages were flooded and a main highway and communication systems were cut.

Army helicopters were rescuing people from rooftops and trees and police and rescuers were using boats to help villagers escape in Sunsari district about 480 kilometres southwest of the capital Katmandu said Home Ministry official Modraj Dotel. Emergency relief supplies were also being sent to the area.

Initial reports said several villagers were swept away by floodwaters but information was sketchy as communication lines had been severed Dotel said.

The villages were flooded after the Kosi river became swollen by monsoon rains. Flooding is common in Nepal during the monsoon season which begins in June and ends in September.

Prime Minister Pushpa Kamal Dahal Prachanda flew to the region on Wednesday with top government officials to assess the situation said Dotel.

A three-kilometre section of the Mahendra highway a main cargo and travel route was also swept away.