"We fear those who are still missing were unable to survive," he said.
There were conflicting reports about the exact number of people on the boat due to the lack of a manifest, but some survivors told officials that about 100 asylum seekers from Lebanon, Pakistan and Iraq were believed to be aboard, said a local police chief, Lt. Col. Deddy Kusuma Bakti.
Survivors said the boat was headed for Australia's Christmas Island.
Lebanon's official National News Agency said 17 Lebanese drowned in the incident. Nine members of a single family were among the Lebanese victims, with a woman and her eight children dying and her husband surviving, the agency reported.
The boat capsized and sank after being hit by up to 6-meter (19-foot) waves hours after leaving Sukabumi early Friday, Zainudin said.
The incident came ahead of new Australian Prime Minister Tony Abbott's first visit to Indonesia next week. He is expected to meet with Indonesian President Susilo Bambang Yudhoyono.
Indonesia has said that the Australian navy's plan to intercept and force back Indonesian fishing boats crowded with asylum seekers could breach Indonesian sovereignty.
- AP