Senior maritime officials in Solomon Islands say they are now investigating claims that a boat passed by when the Global Lesterie got in trouble last week, and eventually sank.
The six crew on board the boat were rescued by a container vessel from their life raft on Sunday, after reports first came through a week earlier that they were in strife.
There were claims the barge, believed to be carrying logs to the capital Honiara, had earlier been detained for failing to meet safety standards.
The acting Director of the Solomon Islands Maritime Safety Administration, Jonah Mitau, says that will still form part of the investigation but they are now also looking at why a passing vessel didn't stop to help.
He says it could be another week before their investigation is complete.
The ship was believed to have sunk between the islands of Savo and Isabel.