Port officials in Papeete say the fire damaged cruise ship Wind Song has been sunk by the French Polynesian authorities.
The vessel, which was badly damaged in a fire off Tahaa last month, was sunk during the night near Tahiti at a depth of about two kilometres.
The action was authorised by the territorial government in apparent defiance of a court order which called for the deferral of the proposed sinking.
The port authorities say they acted because the vessel posed a risk for traffic in the port.
A local parliamentarian, Loic Brigato, has condemned the sinking, saying it violates a court ruling that put the matter in the hands of the French state.
Assessors sent by the court to inspect the wreck found the quay empty when they arrived this morning.