The government in Papua New Guina says a full investigation will be carried out into last week's ferry disaster.
The MV Rabaul Queen sank between the island of New Britain and the mainland city of Lae on 2 February.
A total of 246 people were rescued but more than 100 remain unaccounted for. Six bodies have been found.
PNG's Minister for Transport and Works Francis Awesa says the government will seek the assistance of the Australian National Maritime Safety Authority to try to find out exactly what happened.
The news of the investigation comes amid reports that the vessel may have been overloaded.
Disaster officials say the manifest shows the MV Rabaul Queen was carrying 379 passengers when it went down.
According to some reports, the ship should have been carrying only 350 passengers while other put the vessel's capacity at only 310 people.
Meanwhile, the search has resumed for the bodies of those presumed dead.
The Maritime Safety Authority says two boats and a fixed-wing aircraft resumed search on Monday afternoon after strong winds forced a delay earlier in the day.
A spokesperson, Captain Nurur Rahman, says the search is focusing on an area more than 300 nautical miles from the site where the ferry went down.
He says a vessel will be sent to check uninhabited islands nearby for any survivors once the weather improves.
However, earlier the Authority said that, after 60 hours of searching without finding any survivors, the rescue operation had now turned in to a recovery mission.
Ferry sank fast, says survivor
A 27-year-old Bougainville Island man who survived the ferry disaster has spoken to Radio New Zealand about his harrowing experience.
The man, who did not wish to be named, was on the top deck of the boat when he noticed it go sideways then capsize.
He says people were praying loudly in the ocean and he watched several people die, as they were no longer able to fight the rough seas.
He says he jumped into the ocean as the ship began to sink and grabbed hold of a life raft with several others, managing to stay afloat until help came several hours later.
The man estimates the ship went down in less than 10 minutes.