FIRE crews will battle a bushfire at Lefroy for the third day today as the state's emergency services hope for kinder conditions.

Strong winds of up to 45km/h yesterday saw the blaze more than double in size since it started late on Tuesday, expanding to more than 672 hectares and threatening about 70 homes at the township and along Beechford Road.

The fire was at one point deemed an emergency by the fire service but was downgraded to advice level late in the evening.

An emergency evacuation centre had been set up at the George Town Memorial Hall.

Three bulldozers, trucks from Hobart and 18 firefighting apparatuses carrying 42 personnel from around the North were called upon throughout the day to battle the blaze.

Seven aircraft, including some from Melbourne, were also deployed to dump water on affected areas and enjoyed success in flattening the fire's efforts in the late afternoon.

The two fixed-wing aircraft from interstate each dropped 13,000 litres of retardant on the blaze.

Following the planes' efforts the bushfire passed Lefroy and headed east into thick bush, a fire service spokesman said.

By 8pm the fire had been downgraded in status and power had been restored to all homes in the area.

Police and fire crews ran roving patrols in the area throughout the evening.

Some residents were last night allowed to return to their homes but many were barred or chose to stay away.

Tasmania Fire Service public information officer Michael Watkins said the service expected similar conditions today but remained hopeful overnight rain would help get the blaze under control.

Compressed air foam trucks will be used to compress the fire's edges today, Mr Watkins said.

Longford brigade chief Mike Armstrong urged people in the area to listen to emergency service workers.

"Obviously our main concern is community liaison," Mr Armstrong said.

"Listen to what the fire service tells you and stay safe."

For updates on the Lefroy fire, visit fire.tas.gov.au.