Multiple fire crews were called to the property at Lower Barrington, in the state's northwest, at 10:55am on Sunday.
The Tasmania Fire Service said the house was well alight when crews arrived and the main fire was extinguished by 12:55pm with everyone living there was accounted for.
"The cause was deemed to be accidental and the damage was estimated at $300,000," the a fire service spokesperson said.
A relative set up an online fundraiser via the GoFundMe website with the aim of raising $10,000 to help ease the "devastating loss" suffered by the parents and their five-year-old child and five teenage children,
"Fortunately (the family) had left the house already to come to Christmas lunch, so no one was injured," the fundraiser's organiser stated.
"The results of this fire is catastrophic, the entire house is ruined and the house is completely uninhabitable. However, it could have been a lot worse and we are so thankful the family and pets are safe.
"All items in the home have been destroyed, and with six kids, two dogs, and two cats the cost and effort of replacing necessities is very overwhelming."
After posting the fundraiser on Sunday, the organiser said she was "honestly blown away by the kindness of everyone" after online donors pledged more than $8800 in the space of 20 hours, including one anonymous donor who pledged $1000.
"Just wanted to say what a caring community and everyone is looking out for the family so much," the organiser stated.
Sheffield Fire Brigade, which responded to the house fire, also opened its station on Monday so people could donate physical goods to aid the family.
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