Storms and damaging winds will keep fire danger high across parts of Australia with authorities calling for vigilance after a weekend of significant losses.

About 60 bush and grass fires were burning in NSW on Sunday following earlier heatwave conditions.

Premier Chris Minns said December was shaping up as a particularly dangerous fire period, because of westerly winds and warmer waters off the Pacific Ocean.

“Unfortunately we’re likely to have more volatile weather periods in the years ahead due to the changing climate, Minns told ABC TV on Sunday.

“I’d love to be able to say we’re out of the woods or the worse is behind us but the truth is that’s not the case.”

A heatwave warning has been cancelled after an out-of-control bushfire in Koolewong, not far from built-up areas on the NSW central coast, destroyed at least 12 homes on Saturday.

Another four homes were lost at Bulahdelah on the mid-north coast.

With easing conditions across NSW, firefighters supported by aircraft continued to strengthen containment lines.

But authorities urged the community to stay vigilant with more storms and lighting projected to hit on Sunday.

Federal and state disaster assistance funding has been activated across the central and mid-north coasts, the Upper Hunter, Muswellbrook, Warrumbungle and Dubbo.

More than 250 firefighters, 50 trucks and nine aircraft battled the Koolewong blaze at its peak.

Meanwhile in Tasmania, authorities have confirmed a 700-hectare blaze at Dolphin Sands, near Freycinet National Park on the state’s east coast, was contained after overnight rain.

Nineteen homes were destroyed and 14 others sustained some damage in the fire sparked in the seaside community on Thursday.

More than 120 sheds, caravans, water tanks, carports, garages, electricity transmissions were also damaged.

“With increasing winds and debris still present on properties, conditions pose safety risks to the community,” Tasmania Fire and Emergency Services Commissioner Jeremy Smith said.

The Bureau of Meteorology has issued a severe weather warning for eastern Tasmania. Damaging wind gusts of about 100 km/h are expected from late Sunday night into Monday morning.

About 30 firefighters remain on the fireground continuing to work on extinguishing hot spots.