The landslide has completely buried five houses in the Menawan village, Antara reported.
The bodies of 11 of the 12 landslide victims have not been recovered. Three children are among the dead.
Nineteen others were killed in flooding in North Sulawesi, Antara said.
Noldy Liow, the head of the Regional Disaster Mitigation Agency, said that authorities are working to find other victims of floods and landslides.
Several of the country's districts are still being affected by floods and landslides, he said.