Fires have raged across a huge area of eastern Australia, laying waste to bush, farmland and people's homes

Australians on Wednesday began sifting through the ashes of hundreds of bushfires that have ravaged the country, relieved that their worst fears were unrealised—but wary of a long and brutal summer ahead.

Firefighters were still battling around 140 blazes across the country's eastern seaboard, but a respite from "catastrophic" meant the danger from many fires was downgraded.

The northern state of Queensland remained on high alert, with residents on the north shore of popular holiday town Noosa told to "leave immediately" to avoid an "unpredictable" burning nearby.

Underscoring the risks to residents and , a firefighting helicopter crashed during waterbombing operations in the state.

The pilot survived with "non-life-threatening injuries", a Queensland Ambulance Service spokesman told AFP.

In the worst-hit areas of New South Wales, cooler southerly winds eased conditions—a stark contrast with the gale-force gusts and high temperatures that plagued firefighters for much of Tuesday.

In all, 50 homes were damaged or destroyed, and around 20 people were injured, but most populated areas were spared.

Residents of the small towns of Glenreagh and Nana Glen returned to find houses intact, a nearby 150,000-hectare (370,000-acre) inferno having stopped just short of their doors.

Some of those allowed to return to their properties found nothing but the charred remains of their homes

But on nearby farmland, unlucky families faced homes destroyed and cars transformed into blackened husks.

Queensland Fire and Emergency Services acting commissioner Michael Wassing said another wind change on Wednesday afternoon could worsen several in difficult-to-access areas of the state.

"We've got another tough day today and there's an extended forecast that we're not out of the woods by any means," he said.

Tough conditions were expected to flare again in Queensland and New South Wales at the weekend as the and winds pick up.

"We will not have all these fires contained before then," New South Wales Rural Fire Service commissioner Shane Fitzsimmons said, adding that it could be "many, many weeks" before the situation is fully under control.

"Unfortunately, what we need is rain... and there is certainly nothing in the forecast for the foreseeable future that's going to make any discernible difference."

Firefighters have fanned out across the region, tackling hundreds of blazes

More than 300 new fires began in the state Tuesday, with 19 classified as emergencies. They spanned a distance of almost 1,000 kilometres (600 miles)—from the outskirts of Sydney north toward Brisbane.

"The losses, the damage, the consequences could have been simply enormous across such a broad geographic area," Fitzsimmons said.

New South Wales Police said they had begun investigating whether a small number of the blazes had been deliberately lit, as they made handful of arrests for suspected looting of fire-stricken properties.

The hot, dry continent of Australia has long experienced bushfires, but scientists say climate change is exacerbating , including a prolonged drought in the country's east that has created tinderbox-like conditions.

The Bureau of Meteorology says human-caused climate change is also "influencing the frequency and severity of dangerous bushfire conditions" by increasing temperatures, sapping moisture from the environment and causing an earlier and more extreme fire season.

Some animals had to be led to safety, away from the worst of the fires

The unprecedented wave of bushfires has brought renewed calls for the conservative government to curb fossil fuels and cut greenhouse gas emissions.

However Prime Minister Scott Morrison and other senior ministers have repeatedly refused to answer questions about during the unfolding catastrophe.