The newly appointed Regulator, Hickson Siba confirmed the investigation is underway but could not provide the details.
The MV Rosalie embarked on an inter-island crossing from Pentecost island on Friday and sank off Red Cliff, Ambae early Sunday morning.
Up to 12 people including children were reported to have been on board the vessel.
The RVS Tukoro responded and rescued all 12 passengers and crew before the vessel sank.
All of the occupants including two children were taken to hospital for examination and said to be in good condition.
