A fire that threatened homes in George Town on Tuesday was deliberately lit in a rubbish pile, authorities in Tasmania say, but they are unsure if it was arson.

Four aircraft and 60 ground crew were brought in to fight the blaze which investigators have established began in a rubbish pile.

The Tasmanian Fire Service (TFS) issued an emergency bushfire warning just after 3:00pm on Tuesday for an uncontrolled fire putting houses at Marguerite Street, Alfred Street and Mount George Road at risk.

The blaze burnt through 12 hectares, destroying pasture and damaging power poles.

Northern Deputy Regional Chief Ian Bounds said several properties were under threat initially, however with quick work by ground crews and aircraft, the properties were protected.

"In the initial stages it was a very fast-moving fire being pushed by strong westerly winds," he said.

Mr Bounds said it started close to the town's sports complex and police were trying to track down those responsible for starting the blaze.

"The fire started from carelessness or deliberate acts," Mr Bounds said.

"Investigations have found it was a deliberately lit fire, starting from some refuse left in the recreation area, and investigations are continuing to see if we can identify the perpetrator or perpetrators and police are assisting in that."

Firefighters patrolled the fire scene overnight.

Warning to be on alert

Four aircraft were used to fight the blaze at George Town. ( ABC News: Carla Howarth )

The TFS is appealing for Tasmanians to take care over the next few days as temperatures rise and winds increase.

Mr Bounds asked the public to remain on alert and not be complacent.

"We're moving into a much warmer period and were just asking people to take those extra precautions and be aware it's going to be windy over the next few days and it's going to heat up so don't take any unnecessary risks," he said.



Tony Thorpe, who owns land where the fight occurred, said it was the second time his property had been affected by fire.

"It started over near the cemetery by the look of it and obviously got out of control in the wind," he said.

Mr Thorpe said much of his land had been burnt last year under similar circumstances.