Fire flare-up no cause for concern: TFS

Wind gusts across Tasmania's Midlands have fanned a bushfire but crews insist no ground has been lost in battling the blaze.

The fire near Osterley continued to burn through dense bushland for a sixth day on Friday, with the Tasmania Fire Service maintaining a community alert, despite there being no immediate threat to private property.

"We've still got quite a few crews working on the Osterley fire and there have been a few flare-ups as winds picked up through the afternoon," a spokesman told AAP.

"But we are still confident the fire will remain contained."

More than 2600 hectares of bush has been burnt by the fire, along with two sheds and a vehicle.

The blaze is one of 21 across the state being attended or monitored by the fire service on Friday at the end of a week when more than 80 fires broke out in conditions that were at times hot and windy, sparking total fire bans on Saturday and Friday.

Each fire will be investigated to find a cause.

Many started after flare-ups from smouldering remains after private burn-offs were not properly extinguished, senior fire officers said.

The Osterley fire was not caused by a burn-off, with investigators instead considering natural causes or "human intervention".