About 15 houses escaped damage and residents were told to leave unless willing to defend the properties, after the blaze swept through an area in the suburb of Dynnyrne on Saturday.
A combination of aerial water-bombing aircraft and ground crews worked in tandem to contain the fire.
Investigator Tim McKay, who attended the scene, says a local was brush cutting to clear vegetation when the metal blade of the device struck some rocks and produced sparks which ignited nearby vegetation.
Despite attempts by the operator to extinguish the flames, dry undergrowth and the steep slope he was on made it easy for them to quickly spread.
Tasmania Fire Service Chief Officer Dermot Barry says although accidental, the fire was an example of how easily one can start and get away under the right conditions.
"Yesterday's incident clearly demonstrates how important it is that people maintain vigilance when conducting any work which has the potential to start a fire," he told reporters in Hobart on Sunday.
"Something as simple as having a garden hose on hand can make all the difference."
Mr Barry said the fire was reported at 2.25pm in the vicinity of Proctors Rd, Dynnyrne.
At its peak, 15 homes came under direct threat, while about 1.5 hectares of vegetation was burnt.
An out building on a neighbouring property with an approximate value of $50,000 was also destroyed.
Mr Barry says fuel reduction burning conducted in late November and strategic fuel breaks contributed to the effective suppression of the fire.
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