Police believe human remains found in the rubble of a burnt-out shed are those of 54-year-old Biggenden man Todd Mooney and his 10 year-old daughter Kirra.
Authorities were alerted to a fire on the rural property at Biggenden, 83 kilometres west of Maryborough, at 12:20pm on Tuesday.
The Queensland Fire and Emergency Service said the fire took about seven hours to extinguish and was attended by six crews.
Forensic investigators arrived at the site on Tuesday afternoon to comb the scene for clues.
Detective Inspector Gary Pettiford of the Wide Bay-Burnett Police district said forensic testing would be carried out to confirm the identities.
"We believe that those two people belong to that property," he said.
"This is investigation will go for at least two to three days before we know anything concrete."
He said scientific police and fire investigators had been hampered by the damage to the structure.
"The first phase is to make the structure safe so that our scientific and forensic experts can get in there and commence their investigations," he said.
Detective Pettiford said the man's partner, who is the mother of the child, was not home at the time of the fire.
He said the father and mother were due to be married on the property next week.
"What makes this incident more tragic is the fact that the male adult and the female adult were due to get married next Wednesday," he said.
"There's no history of any poor interactions with members of the community and the same with family members.
"So the whole thing is very, very tragic for the community out there."
Police said it was too early to determine whether the fire had been deliberately lit.
