The hardest hit is the village of Kalonding where cacao plants over 50 hectares of plantations were destroyed, a villager Sahrir said on Friday.
Kalonding is one of the main cacao producing areas in the regency.
Sharir said the flooding inundated the plantation with water surface as high as 50 centimeters.
He said the cacao is the main crop in Mamuju, adding thousands of local people live from cacao farming.
Indonesia is the third largest producer of cacao beans after the Ivory Coast and Ghana, and West Sulawesi is one of the country`s largest producers of cacao beans.
He said the flooding also destroyed corn crop, killing domestic animals including poultry.
Many local people have fled their houses to stay with relatives in other villages.
Sahrir said the people need immediate assistance from the government. (*)