Papua New Guinea authorities are still searching for clues into the disappearance of seven people at sea in the autonomous Bougainville region.
The group which included three health workers, two students and the boat crew have not been heard of since they departed Nissan Island for Buka on 14 June.
Speculation of foul play has emerged in media reports around the disappearance, but so far nothing has been confirmed.
The trip was funded by Save The Children in partnership with the Bougainville health department.
A source on the ground, who wishes to remain anonymous, said some luggage, believed to have belonged to members of the group, was found early on in the search but nothing since.
Save The Children said it was unable to comment because the matter is in the Bougainville government's jurisdiction.
Attempts are being made to reach authorities in Bougainville, which is experiencing problems with its telecommunications network.