The four men were arrested on Wednesday and Thursday in two nearby cities after the boat sank off the southwestern coast of Java island Tuesday, killing among them six children and a pregnant woman, the Cianjur city police chief Dedy Kusuma Bakti said.
"The four helped arrange the boat trip.
They are part of a people smuggling syndicate. Some of them had organised several boat trips to Australia," he said, adding that they could be charged with people smuggling which carries a jail sentence of between five and 15 years under the country's immigration law.
The number on the overloaded boat was unclear. Police have said around 200 were aboard, but an asylum-seeker has said 250 people made the perilous journey.
Rescuers have saved 189 asylum seekers which included Iranians and Sri Lankans and the search effort continued Saturday, rescue operation chief Rochmali, who like many Indonesians goes by one name, said.
Australian authorities alerted Indonesia of the incident Tuesday evening, just days