Volatile fire conditions caused blazes to flare across the state on Sunday, with a handful of emergency warnings still active for towns at very high risk.

An uncontrollable and fast-moving fire southwest of Hobart poses a major threat to Waterloo, Surges Bay, Brooks Bay, Glendevie and Police Point.

Burning embers falling on the areas will threaten homes before the main blaze and property loss is "highly likely" at Waterloo, the Tasmania Fire Service says.

The fire alert for Geeveston, Port Huon and Cairns Bay has been downgraded but residents are urged to leave while they still can.

More than 21 fires, some of which started before Christmas, are burning out of control across Tasmania.

Some 191,000 hectares have now been destroyed.

Geeveston IGA owner Matthew Nicholas has evacuated his home twice over the past fortnight but told AAP he was staying put for the time being.

"We're not under threat per se, because they did a lot of backburning which I'm grateful for," he said.

"We stick together but I think we're all getting a bit weary. It's on and off, I just hope it's not going to be like this for the next month."

A difficult-to-control fire is also threatening Liawenee, Brown Marsh, Moon Marsh, London Lakes and Reynolds Neck in the central plateau.

Eleven watch and act alerts also place for blazes across Tasmania.

The blazes could burn for weeks, prompting the federal government to open the disaster recovery allowance for bushfire-affected small business owners and employees.

Premier Will Hodgman on Sunday visited the Huonville evacuation centre, where hundreds are sheltering.

He slapped down calls for an immediate review of the state's fire response, confirming examinations will happen when the crisis is over.

"The last thing anyone needs now is armchair critics or experts who think they know what they're talking about," he said.

"We have some of the best firefighting capabilities in the world here in Tasmania and they are currently under enormous stress - we don't want anyone to add to that."

A cool change is expected to sweep the state on Sunday night and bring a few millimetres of rain.

Forecasters say there is also a "reasonable chance" of state-wide rain on Thursday, about 10-20 millimetres.

"That is the most optimistic rain event that we've seen in the last couple of weeks," the Bureau of Meteorology's Simon McCulloch told reporters.

The fires have claimed three homes and a near-century-old trapper's hut, and damaged the popular Tahune Airwalk tourist attraction.

Aerial footage has shown vast tracks of blackened wilderness in the southwest.

Australian Associated Press