"A scene examination is under way. The investigators are working to establish the cause of the fire and to identify the deceased person."
A post mortem examination would be carried out to establish the cause of death, police said.
Police and the fire brigade both said this morning they had not reached any conclusions, although the site was roped off and a scene guard had been placed overnight.
A thorough search was under way and a forensic examination launched.
The Fox Glacier Volunteer Fire Brigade was called about 3.35am to the property, which sits on Maori reserve land about 730m west of State highway 6 on the Mai Mai straight, south of the Karangarua River.
Fire chief John Sullivan said a male relative of the occupant had arrived back from an overnight hunting venture about 3am to find the shed a smouldering heap of iron.
When the brigade arrived, the man's vehicles were parked up but there was no sign of their owner anywhere on the property.
"By the time we got there it was pretty much a smouldering heap of collapsed iron," Mr Sullivan said.
The relative who discovered the burning ruins had left the property yesterday afternoon to go for an overnight possum shooting trip in the surrounding area.
Franz Josef Glacier police arrived at the fire scene while the brigade was there, and an initial supervised search for the man, under the cover of darkness, proved unsuccessful, Mr Sullivan said.
"It's a bit of a mystery. We had a pretty thorough search through ... we couldn't find anything obvious. We're just keeping our fingers crossed."
The property had no close neighbours and was reasonably isolated. Access was via an old logging road and a former section of the old main road, he said.
The large barn-style shed was used as a woodworking workshop, with the owner living in a part which had been converted to living quarters on a mezzanine floor.
