Three residents have been confirmed dead, with several missing and more than 150 houses destroyed as blazes rage from the mid-north New South Wales coast to the Queensland border.

The firefighters, including 25 volunteers, left from Hobart aboard an Airforce Hercules early on Sunday morning.

Tasmania Fire Service acting deputy chief officer Shane Batt said to begin the firefighters would be deployed to the Northern Tablelands and the Clarence Valley regions.

"The fire activity might increase somewhere else so they do get moved around," he said.

The officers work on a seven day rotation with the TFS expecting to supplement 25 to 30 firefighters each week for three or four rotations until NSW no longer requires assistance.

"That's something we can easily manage without depleting all of our firefighters," acting deputy chief officer Batt said.

"We will share those 25 to 30 people across the state and make sure we are still providing a firefighting capacity for Tasmania as well."

Acting deputy chief officer Batt said it was a great opportunity for Tasmania to repay the favour NSW firefighters have provided over the past few years.

"They have send multiple crews down to us, up to 1000 in the past," he said.

"It gives us an opportunity to support them in their hour of need."

Sixteen Parks and Wildlife Service firefighters will also head to NSW on Sunday to support the firefighting effort.

Twenty-six Tasmanian personnel are already the fire ground assisting with the Kangawalla fire near Glen Innes.

More than 70 fires are still burning across NSW.