DNA tests are currently being carried out on the remains, which include bones, a jaw that with some prosthetic teeth, as well as some melted metal pieces. Investigators said the evidence suggests that a human body was hacked to pieces and burnt.
Remains of clothing were also found at the abandoned site, in a valley some two hours' hike from the coast.
French chief investigator José Thorel, based on the island of Tahiti, did not rule out the possibility that the remains are from the missing German, but said the DNA evidence, which has been taken to Paris, could take weeks to analyze.
Police are searching for a local hunter, the last person to be seen with the traveller, who was sailing around the world with his partner, a 37-year-old woman.
She reported that the hunter offered to take him on a trip into the island's interior. He then returned alone, telling the woman that her partner had been injured in an accident and needed help.
Later the traumatized woman told the local Dépêche de Tahiti newspaper that the hunter threatened her, sexually abused her and tied her to a tree.
The couple had been travelling around the world in a catamaran, and had landed on Nuku Hiva, one of the Marquesas islands belonging to French Polynesia in the South Pacific, two weeks ago.
The missing man is a 40-year-old experienced traveller from Hamburg, though no name has been released. The German Foreign Ministry spokeswoman said, "The Foreign Ministry and the Federal police are aware of the case and in contact with local authorities."