At least 11 people were buried by a landslide triggered by heavy rain on Indonesia's Java island on Saturday, including villagers who were harvesting a crop of ginger, a disaster official said.

Police and soldiers were helping residents to clear the mud and debris to look for victims after the landslide in the village in the Ponorogo area of East Java, said National Disaster Management Agency (BNPB) spokesman Sutopo Purwo Nugroho.

Up to 30 houses had been engulfed by the landslide and the exact number of people missing was still unclear, with heavy equipment needed to shift the earth, said Nugroho.

Rescue efforts were also hampered by people flocking to the area to see the landslide and causing traffic jams, he said.

The local disaster mitigation agency had warned of the risk of a landslide due to recent rain, and some people had only returned to the village on Saturday after staying the night in a shelter, said the official.