"Officers from the Whanganui CIB and Fire Scene Investigators are working to establish the cause of the fire. Preliminary indications suggest a lit candle may have started the fire,'' Mr Wood said.
"A thorough scene examination is underway at the property and officers have also been speaking with the man's friends and associates to piece together his movements before the fire.''
The fire is not believed to have been suspicious, and the man's death will be referred to the coroner, police said.
Further details about the man would be released once his next of kin had been advised.
Anyone with information is asked to contact Marton police on (06) 327 6555. Information can also be provided anonymously to Crimestoppers on 0800 555 111.
The incident was initially reported as a tent fire