Britain's King Charles was accused of "genocide" by an Indigenous senator at Australia's Parliament House on Monday, moments after he delivered a speech in which he paid his "respects to the traditional owners of the lands".

Charles, on his 16th official visit to Australia and his first major foreign trip since being diagnosed with cancer, had finished speaking when independent senator and Indigenous activist Lidia Thorpe shouted 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."

Thorpe, who has disrupted previous events protesting over the colonisation of Australia, was stopped from approaching the king, who spoke quietly to Prime Minister Anthony 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 Charles and Queen Camilla 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.

The visit to parliament followed a trip to the Australian War Memorial in Canberra where the royal couple met more than a thousand well-wishers including Hephner, a nine-year old alpaca in a suit with a crown perched atop his fluffy white head.

Hephner, named after 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.

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. (Reuters)