The 56-year-old was last seen on October 8 in the Brighton area and, despite numerous reported sightings, police have no firm leads on his whereabouts.
Senior Sergeant Craig Brown said another sighting was reported to police yesterday afternoon, but it came to nothing.
''Someone out that way believed they had seen him,'' he said.
''It was checked out by Mosgiel police ... and that didn't come to anything.''
Any information or further sightings would be ''greatly appreciated'', Snr Sgt Brown said.
Mr Carter is 165cm tall and of thin build.
Anyone who sees him or with information about his whereabouts should contact Dunedin police on 471-4800.
Information can also be provided anonymously to Crimestoppers on 0800 555 111.
