Police said they were searching through wrecked houses for bodies and say scores people are still missing after the fires that have raged on the Australian island state for the past three days.
Multiple fires are still blazing but have already destroyed more than 100 houses and 20,000 hectares of bushland, mainly around the state's southern peninsula.
Westpac Police rescue helicopter crewman Sgt. Matthew Drumm surveys the fire near Dunalley, east of the Tasmanian capital of Hobart (AP)
Almost 1200 people were evacuated by boat after taking refuge along the coast, while several hundred in inland areas are still stranded due to the closure of the area's main highway. A pall of smoke now hangs above much of the state.
Police said on Sunday there were no known fatalities but they hold grave fears for a small number of people reported missing.
"We have to brace ourselves for the fact we may locate one or more deceased," said Scott Tilyard, Tasmania's acting police commissioner.
"A lot of premises need to be checked. Until we've had the opportunity to check every one of those locations we won't be in a position to confirm there have been no deaths."
Police said about 100 people from the area were unaccounted for and had yet to make contact with family or authorities.
"That is not to say that those people necessarily have come to any harm, but obviously we can't totally eliminate that until we've had confirmed contact with those individuals," said Mr Tilyard.
A bushfire burning near Ouse, north of Hobart, Tasmania (EPA)
The fires came amid a nationwide heatwave which has led to temperatures of over 104F (40C) across much of the country. In the state of Victoria, a major blaze in the southwest remains out of control and fire fighters are battling to control it before more hot weather arrives this week.
Survivors from the ruined Tasmanian townships have begun to recount their experiences as they rushed to safety and took refuge from the flames in canals and at beaches.
A resident of the worst-hit town of Dunalley, Joel Clements, described rushing to safety and watching his home burn to the ground.
"We thought we were prepared but we only just made it to the water," he told Channel Ten.
"We had flames coming across the top. We made it to the safety point out at the bay and basically just watched the devastation from out there." A 92-year-old evacuee from Dunalley, Patricia McCauley, said: "We didn't have time to get frightened. We just had to get out without anything."
Simon Brooks, a resident from the town of Boomer Bay, tried to battle the fire and save his home but eventually evacuated. Returning to examine the ashes of his house, he told the Hobart Mercury newspaper: "We are trying to work out a strategy from here. It's scary Armageddon stuff."
The Queen sent her condolences to Tasmania, expressing "deep concern" at the destruction and offering her sympathy to those who had lost homes and livelihoods.
"I offer my support and admiration for the firefighters, volunteers and emergency services officers who have been working tirelessly to contain the situation," the Queen said in a written message.