An extreme weather system that spawned torrential rains has triggered landslides on Sumatra, leaving at least 19 people and seven people known to be missing.

Tonnes of mud, rocks and uprooted trees rolled down a mountain late Friday, reaching a river that burst its banks and tore through mountainside villages, said Doni Yusrizal, who heads the local disaster management agency.

Rescuers by Saturday pulled out seven bodies in the worst-hit village of Koto XI Tarusan, and recovered three others in two neighbouring villages, Yusrizal said.

Rescuers retrieved six bodies in Pesisir Selatan and three more in the district of Padang Pariaman, bringing the death toll to 19, the National Disaster Management Agency said on Sunday.

The agency said at least two villagers were injured by the flash flood and rescuers are searching for seven people who are reportedly still missing.

It said more than 80,000 people had fled to temporary government shelters after the flood and landslide buried 14 houses, while 20,000 houses were flooded up to the roof in nine districts and cities in West Sumatra province.

“Relief efforts for the dead and missing were hampered by power outages, blocked roads covered in thick mud and debris,” Yusrizal said.

Heavy rains cause frequent landslides and flash floods in Indonesia, where millions of people live in mountainous areas or near flood plains.

-AAP