A seventh man managed to survive being stranded for about 12 hours in waters near the Queensland town of Seventeen Seventy, according to authorities.
He survived by clinging to the boat's hull before treading water until he was seen by a passing yacht, local media said.
Search teams have found debris but no trace of the missing men.
The 17m (55ft) commercial fishing trawler, Dianne, capsized at 19:30 local time on Monday (09:30 GMT) and sank about five hours later.
