Rescue workers and police were struggling to reach the affected areas as roads were cut off by floods following the rains, Syahroni, a provincial police spokesman said.
Heavy machinery and police reinforcements have been sent to affected areas to help with the recovery and find bodies.
"We expect the number of victims to increase," Syahroni said. Landslides have been an increasingly common occurrence in recent years in Indonesia.
Deforestation has meant that there is little vegetation to hold soil during the country's tropical downpours.
It is a particular problem in densly populated Java, where many people live on flood plains and near rivers.