King Charles says signs of climate change in Australia 'unmistakable'

King Charles warned of "overwhelming" climate dangers in an address at Australia's parliament on Monday, saying the growing ferocity of bushfires and floods were an "unmistakable sign" of a sweltering planet.

The monarch urged Australia -- a longtime climate laggard with an economy geared around mining and coal -- to assume the mantle of global leadership in the race to slash emissions.

"It's in all our interests to be good stewards of the world," he said in his first speech inside Australia's parliament as head of state.

The 75-year-old sovereign is on a nine-day jaunt through Australia and Samoa, the first major foreign tour since his life-changing cancer diagnosis earlier this year.

His environmental advocacy -- which has seen him dubbed the "climate king" -- is sure to resonate in a country scarred by fires and floods.

The "magnitude and ferocity" of these natural disasters was accelerating, said Charles, who described the "roll of unprecedented events" as "an unmistakable sign of climate change".

"This is why Australia's international leadership on global initiatives to protect our climate and biodiversity is of such absolute and critical importance."

Charles paid particular tribute to Indigenous "traditional owners of the lands" who had "loved and cared for this continent for 65,000 years".

At the end of his speech, as the hearty applause receded, an Indigenous lawmaker shocked the audience with her own interjection.

"Give us our land back!" screamed independent senator Lidia Thorpe, who had earlier turned her back on the king as the crowd stood for the national anthem.

"This is not your land, you are not my king" the lawmaker added, decrying what she described as a "genocide" of Indigenous Australians by European settlers.

- 'Unmentionable parts' -

Charles will later visit a purpose-built lab at Australia's public science agency, which is used to study the bushfires that routinely ravage swathes of the country.

He will then stroll through plots of native flowers at Australia's national botanic garden, discussing how a heating planet imperils the country's many unique species.

A lifelong greenie, Charles' passion for conservation once saw him painted as a bit of an oddball.

He famously converted an Aston Martin DB6 to run on ethanol from leftover cheese and white wine, and once confessed that he talked to plants to help them grow.

In a brief moment of levity during an otherwise weighty address, Charles spoke fondly of his teenage experiences as a student in rural Victoria.

This included "being given unmentionable parts of a bull calf to eat from a branding fire in outback Queensland".

- Alpaca admirer -

Bearing a swag of new military honours bestowed over the weekend, Charles had earlier laid a wreath in the Hall of Memory at Australia's imposing national war memorial.

Robert Fletcher and his suit-wearing alpaca "Hephner" were among the polite crowd of royal super fans and young families queuing outside to catch a glimpse.

"Hopefully we'll get in today to see the king and queen. And hopefully a selfie or something," Fletcher told AFP while holding his nine-year-old alpaca on a short leash.

Chloe Pailthorpe and her children travelled to Canberra from a small rural town nearby.

"I've been writing to the royals since I've been about 10," she told AFP.

"My kids have been writing to the royals. We just love what the royals do."

Many of Australia's state premiers will miss a reception for the king hosted in the parliament's "great hall".

Tied up with overseas travel, elections, and other pressing government business -- their absence suggests the throne does not have the pulling power it once did.

Australians, while marginally in favour of the monarchy, are far from the enthusiastic loyalists they once were.

Visiting British royals have typically carried out weeks-long visits to stoke support, parading through streets packed with thrilled, flag-waving subjects.

But the king's fragile health this time around has seen much of the typical grandeur scaled back.

Aside from a community barbecue in Sydney and an event at the city's famed opera house, there will be few mass public gatherings.