Among the thousand plus well-wishers gathered to greet King Charles and Queen Camilla at the Australian War Memorial in Canberra on Monday was Hephner, a nine-year old alpaca in a suit with a crown perched atop his fluffy white head.

Hephner, named in honor of Playboy founder Hugh Hefner, waited for hours alongside owner Robert Fletcher and long lines of others outside the memorial for the chance to greet the royal couple on their one-day tour of the capital.

"He has many outfits and this is one we've saved specifically for today," said Fletcher. "One king meets another king."

Hephner's patience paid off. On a 30-minute walk to greet the crowds, Charles stopped to pat the alpaca, pulling back with a laugh when Hephner snorted in his face.

Charles' 16th official visit to Australia is also his first major foreign trip since being diagnosed with cancer in February.

Prime Minister Anthony Albanese and other senior officials hosted a reception for the monarchs in parliament later on Monday where Charles gave a brief speech about his time in Australia as a teenager and the threat of climate change.

Moments later, independent senator and indigenous activist Lidia Thorpe strode up toward the podium shouting that she did not accept Charles' sovereignty over Australia.

"You committed genocide against our people," she said. "Give us our land back. Give us what you stole from us - our bones, our skulls, our babies, our people. You destroyed our land. Give us a treaty. We want treaty."

Security stopped her approaching the king, who spoke quietly to Albanese on the podium but was otherwise unfazed. Thorpe was then escorted out of the chamber.

The protest was an outlier among a stream of tributes to the monarchs from dignitaries and well-wishers in the crowds.

Albanese praised Charles for his long advocacy about the threat of climate change and spoke about the respect Australians had for their monarch.

His speech made only a passing reference to the Republican cause, which Albanese and much of his center-left Labor party support.

"The Australia you first knew has grown and evolved in so many ways," he said. "Yet through these decades of change, our bonds of respect and affection have matured - and endured."

Albanese shelved plans for a referendum on turning Australia into a republic after a government-backed referendum to create an indigenous advisory body was defeated earlier this year.

The royal couple continue their visit to Australia in Sydney on Tuesday, before heading to Samoa for a meeting of countries in the British Commonwealth.