A global appeal to help Australian firefighters tackling catastrophic bushfires raised more than Aus$25 million on Monday, as swaths of the country suffered extensive damage and the death toll from the long-running crisis hit 24.

East coast seaside towns were plunged into darkness, ash rained down on rural communities and major cities were again cloaked in choking smoke, even as stunned Australians tried to regroup amid a wave of cooler air and light rain.

The the crisis has seen an area roughly double the size of Belgium burnt
The the crisis has seen an area roughly double the size of Belgium burnt AFP / PETER PARKS

The weekend marked some of the worst days in the country's deadly bushfire crisis, with hundreds more properties destroyed and the overall death toll climbing to 24, including a man who died Saturday trying to save a friend's home.

Comedian Celeste Barber used her international social media fame to launch a Facebook fundraiser for firefighters that had surpassed its Aus$25 million ($17 million) target in just three days with donations from all over the globe.

Climate change has pushed up land and sea temperatures and led to more extremely hot days and severe fire seasons
Climate change has pushed up land and sea temperatures and led to more extremely hot days and severe fire seasons AFP / SAEED KHAN

American pop star Pink said she would donate US$500,000 to the firefighters, a donation matched by Australian actress Nicole Kidman.

World number one tennis player Ashleigh Barty pledged to hand over all her winnings from this week's Brisbane International tournament -- potentially US$250,000 -- to the Red Cross.

Tens of thousands of volunteer firefighters have been hailed in Australia and across the world for their unrelentling battle against the blazes
Tens of thousands of volunteer firefighters have been hailed in Australia and across the world for their unrelentling battle against the blazes AFP / SAEED KHAN

Around 200 fires continued to burn Sunday, many out of control, although only a handful prompted emergency warnings as temperatures dipped.

Everywhere, millions of beleaguered residents struggled to come to grips with a catastrophe that has taken place on a near-continental scale, unfurled over months, altering daily life.

An area roughly double the size of Belgium has been burnt
An area roughly double the size of Belgium has been burnt AFP / Saeed KHAN

"We're in uncharted territory," New South Wales Premier Gladys Berejiklian said. "We can't pretend that this is something that we have experienced before. It's not."

Authorities have struggled to keep pace with the severity of the crisis -- which has now scorched an area almost the size of Ireland.

While bushfires are common in Australia's dry summers, climate change has pushed up land and sea temperatures and led to more extremely hot days and severe fire seasons.

Australian bushfires have turned the sky red and orange in Cooma, New South Wales
Australian bushfires have turned the sky red and orange in Cooma, New South Wales AFPTV / Saeed KHAN
Everywhere, millions of beleaguered residents struggled to come to grips with a catastrophe that has taken place on a near-continental scale, unfurled over months and altered daily life
Everywhere, millions of beleaguered residents struggled to come to grips with a catastrophe that has taken place on a near-continental scale, unfurled over months and altered daily life AFP / PETER PARKS

Prime Minister Scott Morrison on Saturday announced the country's largest military call-up in years, mobilising up to 3,000 reservists to assist exhausted volunteer firefighters.

Warships and combat helicopters have already been repurposed to help with the largest maritime evacuation in Australia since World War II -- moving to safety some of the 4,000 people trapped for days on the foreshore of Mallacoota, midway between Sydney and Melbourne.

Thick smoke from bushfires has blanketed towns in Bemboka, in Australia's New South Wales state
Thick smoke from bushfires has blanketed towns in Bemboka, in Australia's New South Wales state AFP / SAEED KHAN

Up and down the coast, thousands of people remained displaced and many more weighed an uncertain future.

Noreen Ralston-Birchaw, 75, lost her home in the southeast coastal town of Mogo on New Year's Eve and said she was unsure what to do.

"At this very moment, I don't want to go back and see my house laying burnt on the ground," she told AFP. "I don't want to rebuild there."

Morrison also announced the establishment of a Bushfire Recovery Agency to run for at least two years and help survivors get back on their feet, a signal that the path ahead will be long and difficult.

Even for those not in the fires' direct path, the crisis has put Australia's much-admired outdoor lifestyle on hold: barbecues have been barred under blanket fire bans, top sporting events have been called off and beach trips cancelled.

The country's distinctive flora and fauna will take years or decades to recover -- countless thousands of gum trees have been lost and experts on Kangaroo Island said half the koala population has been wiped out.

Queen Elizabeth II on Sunday said she was "deeply saddened" by the fires, and thanked the emergency services "who put their own lives in danger" to help communities.

Sunday brought milder conditions, including some rainfall in New South Wales and neighbouring Victoria state, but some communities were still under threat from out-of-control blazes, particularly in and around the town of Eden in New South Wales near the Victorian border.

"The sky is still red," said John Steele, 73, who was evacuated with his wife from their rural property north of Eden late Saturday. "We're not out of the woods yet."

In Cooma, in inland southern New South Wales, the fire crisis turned into a flood disaster when a large tower carrying 4.5 million litres of water collapsed, sweeping away cars and filling homes with mud.

"First bushfire and now flood, back-to-back disasters," a shaken resident who asked not to be named told AFP.

Flights were cancelled, galleries were closed to safeguard public health and a large consignment of face masks was being brought in.

In some rural areas affected by fires, police patrolled the streets amid reports of looting and break-ins.