Hundreds of people fled submerged homes, some of which were swept away by flash floods, Jati said.
Hundreds of people were involved in rescue efforts, but distribution of aid and relief is hampered by power cuts, blocked roads and the remoteness of the area that's surrounded by choppy waters and high waves, he said.
Photos released by the agency showed rescuers and police and military personnel taking residents to shelters, while roads are covered by thick mud and debris.
Severe flooding also has been reported in Bima, a town in the neighboring province of West Nusa Tenggara, forcing nearly 10,000 people to flee, Jati said.
Seasonal downpours cause frequent landslides and floods and kill dozens each year in Indonesia, a chain of 17,000 islands where millions of people live in mountainous areas or near fertile flood plains.
In January, 40 people died in two landslides in West Java province.