The Maritime Safety Authority in Solomon Islands says severe weather could have played a part in the sinking of the Solfish 001 near the Santa Cruz Islands last week.
Investigations are underway into the sinking of the vessel about 100 kilometres north of Santa Cruz, which left 49 passengers and crew stranded in life rafts for several days before being rescued on Saturday.
The acting director of the Maritime Rescue Co-ordination Centre, Brian Aonima, says the ship was a former fishing trawler from China that was converted to carry passengers and cargo about three years ago.
He says it was sea worthy but sailed in rough conditions last week.
"It was very high swells and also the weather forecast, wind speed was about 15 to 25 knots. It was very rough weather for Temotu Islands Province."
Brian Aonima says he believes poor weather could have caused the ship's sinking but investigators still need to speak to the captain before confirming the cause.