Heavy rains triggered a landslide in Banaran village in East Java province's Ponorogo district. Residents had defied an evacuation order from the night before to harvest crops, authorities said.
The disaster mitigation agency said 27 people were buried, while a local army chief put the number at 38, based on reports from villagers.
The landslide overturned vehicles, shattered and buried buildings, and left a massive scar on a hillside where lush vegetation had been torn away, the Associated Press reported.
Residents were harvesting ginger on a hillside when they were hit, Sutopo Nugroho, spokesman for the National Disaster Management Agency said.
Nugroho said residents had been warned about the threat of a landslide by local authorities and evacuated the area the night before. But they returned in the early morning to work.
A search operation involving soldiers, police and local volunteers was under way.
Local media reported its remote location hindered rescue efforts.
Widespread flooding triggered several deadly landslides in Indonesia in mid 2016.