Eleven people were killed and dozens were missing after torrential rains and landslides battered one of Indonesia's outermost islands on Monday, the country's disaster agency said.

The National Disaster Mitigation Agency's spokesperson Abdul Muhari said on Kompas TV that, according to the latest information from local officials on the Riau Islands, "11 body bags had been filled" and "50 people are estimated missing".

Pictures provided by the agency showed mud and debris from the landslides had flattened and fully covered the houses that were near the edge of a cliff on Serasan island, between Borneo and mainland Malaysia.

Parts of torn metal roofs were visible.

Riau Islands Disaster Mitigation Agency's spokesperson Junainah added that the communication network in the affected area was cut off, making it hard to get the latest information.

"The weather is unpredictable. The wind is strong and the waves are currently high," said the official, who like many Indonesians goes by one name.

Muhari added that access to the far-flung island would also be hard for rescue officials.

"Normally it take five hours by fast boat," he said. "Tomorrow the National Disaster Mitigation Agency will deploy a helicopter to speed up the logistics delivery process".

Indonesia is prone to landslides during the rainy season, aggravated in some places by deforestation, and prolonged torrential rain has caused flooding in different areas of the archipelago nation.

Floods in Banjar district, in the Indonesian part of Borneo, has inundated more than 17,000 houses and disrupted lives for a month.

Neighbouring Malaysia also suffered torrential rains provoking vast floods. At least four people have died and nearly 41,000 were evacuated last week.

In 2020, Indonesia's capital Jakarta and nearby cities saw some of their deadliest floods in years after downpours triggered landslides.

At least 67 people died in that disaster.