King Charles III will spend six days in Australia before moving on to Samoa
King Charles III will spend six days in Australia before moving on to Samoa AFP

King Charles III touched down in Australia Friday, kicking off the most strenuous foreign trip since his life-changing cancer diagnosis eight months ago.

After a gruelling 20-plus hour journey, the 75-year-old monarch and his wife Queen Camilla landed in a rain-sodden Sydney, and were greeted by local dignitaries and posy-bearing children.

"We are really looking forward to returning to this beautiful country to celebrate the extraordinarily rich cultures and communities that make it so special," the couple said in a social media post ahead of their arrival.

The king is on a nine-day tour of his far-flung Australian and Samoan realms that will feature a public barbecue, famed landmarks and reminders about pressing climate dangers.

He is the first reigning sovereign to set foot Down Under since 2011, when thronging crowds flocked to catch a white-gloved wave from his mother Queen Elizabeth II.

His long-planned trip is designed to bolster the monarchy among an increasingly ambivalent Australian public, whose British heritage is now just one element in a melting-pot nation.

There was an early hiccup, however. Plans to project a montage of images of Charles onto the sails of Sydney's famed Opera House were briefly delayed because a cruise ship called the Queen Elizabeth was blocking the view.

"I think most people see him as a good king" said 62-year-old Sydney solicitor Clare Cory, who like many Australians is "on the fence" about the monarchy's continued role in Australian life.

"It's a long time. Most of my ancestors came from England, I think we do owe something there," she said, before adding that Australia now looks more to the Asia-Pacific region than a place "on the other side of the world."

Still, Australia is a land of many happy memories for Charles and the trip is said to be personally important to him after a period of cancer treatment.

He first visited as a gawky 17-year-old in 1966, when he was shipped away to the secluded alpine Timbertop school in regional Victoria.

"While I was here I had the Pommy bits bashed off me," he would later remark, describing it as "by far the best part" of his education.

Bachelor Charles was famously ambushed by a bikini-clad model on a later jaunt to Western Australia, who pecked him on the cheek in an instantly iconic photo of the young prince.

He returned with wife Diana in 1983, drawing mobs of adoring fans eager to see the "people's princess" at landmarks like the Sydney Opera House.

In 1994, a would-be gunman fired two blanks at Charles as he gave a speech on Sydney harbour -- a mock assassination staged as a human rights protest.

With six days in Australia and five more in Samoa, it will be Charles's longest overseas tour since starting treatment for an undisclosed form of cancer.

He made a brief trip to France this year for D-Day commemorations.

Prime Minister Anthony Albanese, a lifelong republican, has made no secret of his desire to one day sever ties with the monarchy.

Following the death of Queen Elizabeth, his government replaced the monarch's visage on the country's $5 note with an Indigenous motif.

A recent poll showed about a third of Australians would like to ditch the monarchy, a third would keep it and a third are ambivalent.

For now, at least, the question of a republic is a political non-starter.

Charles's looming presence has so far done little to stoke republican sentiment.

He carefully tiptoed around the question on the eve of his arrival, reportedly saying it was ultimately a "matter for the Australian public to decide".

Then Prince Charles is greeted by members of the public during a visit to Brisbane, Australia in 2018
Then Prince Charles is greeted by members of the public during a visit to Brisbane, Australia in 2018 AFP
A recent poll showed about a third of Australians would like to ditch the monarchy, a third would keep it and a third are ambivalent
A recent poll showed about a third of Australians would like to ditch the monarchy, a third would keep it and a third are ambivalent AFP