The fallout is continuing after Indigenous senator Lidia Thorpe challenged King Charles during a welcome reception in Australia's parliament.

At a gathering in Parliament House in Canberra on Monday, the Independent senator for Victoria told the monarch he was not her king.

“You are not our king. You are not sovereign,” she shouted.

“You committed genocide against our people. 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.”

Senator Lydia Thorpe yells at King Charles in Parliament's Great Hall. – Reuters

On Tuesday, Thorpe justified her roundly criticised protest action against King Charles, saying she had written to the monarch multiple times and he ignored her.

Thorpe said her repeated written requests for a meeting and a "respectful conversation" with the monarch had been ignored every time.

"That wasn't afforded to me, so I did that for my people. I did that for my grandmother, and I wanted the world to know that we need a treaty here and we want an end to this ongoing war against first peoples in this country," she said.

"I don't subscribe to assimilating myself into the colonial structure."

Thorpe doubled down on her accusation the King was complicit in the genocide of Indigenous people by remaining silent.

"Why doesn't he say, I am sorry for the many, many thousands of massacres that happened in this country and that my ancestors and my kingdom are responsible for that," she said.

Charles was embraced by an Indigenous elder after a welcome smoking ceremony on Tuesday in the birthplace of Australia's urban Aboriginal civil rights movement in Sydney.

Charles met with Indigenous elders at the National Centre for Indigenous Excellence in inner-city Redfern, including "bush tucker" – or native food – chef Aunty Beryl Van-Oploo, who served kangaroo pies.

King Charles and Queen Camilla at community events in Sydney. – AP

The king was embraced by elder Michael Welsh, and a woman introduced herself as a member of the Stolen Generation – a reference to Aboriginal children systematically removed from their families decades earlier. "Welcome to this country," she said.

While the atmosphere at Redfern was respectful, some people who came to see the king expressed sympathy for Thorpe's actions.

"We've got stories to tell and I think you witnessed that story yesterday," Metropolitan Local Aboriginal Land Council Chairperson Allan Murray said.

Former Olympic athlete Nova Peris, who was the first Indigenous woman elected to the federal parliament, wrote in a social media post she was "deeply disappointed" by Thorpe's actions, which "do not reflect the manners, or approach to reconciliation, of Aboriginal Australians at large".

Thorpe was criticised by Peris for protesting despite swearing allegiance to the Crown when she was sworn in as a senator.

Thorpe said she had taken the oath "under duress". "I sought permission from my family. It was a very very difficult thing to do as a black sovereign woman," she said.

King Charles and Queen Camilla on stage with Prime Minister Anthony Albanese and his fiancee Jodie Haydon. – AAP

Emotions around Indigenous rights and Australia's colonial history are raw after a national referendum on whether to alter Australia's constitution to recognise Aboriginal people was rejected last year.

Charles referred to Australia's "long and sometimes difficult journey towards reconciliation" his a speech before he was heckled by Thorpe.

King Charles spoke quietly with Prime Minister Anthony Albanese while they sat on a podium in the Great Hall as security officials stopped Thorpe from approaching further and escorted her from the room.

Thorpe, who was a guest at the event, was criticised by other guests at the reception including former Liberal prime minister Tony Abbott and Victoria Cross recipient Keith Payne.

Opposition Leader Peter Dutton labelled the senator's protest an act of "self-promotion" and said she should consider resigning.

"People need to express themselves respectfully and sometimes people make it all about themselves and I think that's what yesterday was," he said.

Labor government minister Amanda Rishworth said Senator Thorpe’s actions were “pretty disrespectful and not just to the King, but to the many great Australians that had gathered in the Great Hall”.

“We’re pretty shocked and didn’t quite understand why this was going on, so it was very disrespectful,” she said.

“But it didn’t put a dampener on … the very positive rest of the welcome ceremony, which I think was really very positive.”

King Charles and Queen Camilla attend a community barbecue during a visit to Parramatta. – Reuters

NSW Premier Chris Minns, who hosted a community barbecue for the royal couple, said Senator Thorpe's protest was "grossly disrespectful".

"Everything that particular senator does seems to revolve around herself, as if she's attempting to make herself, that senator, the focus of all attention," he said.

Sydney Lord Mayor Clover Moore added, "I think it's not their fault that we're not a republic. It's ours, the Australian people. We voted for this. It's important to be respectful."

Nationals MP Bridget McKenzie said she was appalled.

“If you’re not a fan of King Charles and Queen Camilla, don’t accept the prime minister’s invitation,” she said.

The federal opposition is considering raising a censure motion against Senator Thorpe in the upper house when it next sits on November 8.

Under glorious spring skies, the king later visited a social housing project designed with the support of his King's Trust Australia charity in the inner suburb of Glebe.

He toured the construction site with Albanese, who grew up on a public housing estate.

Claude Tighe, an Indigenous man in Glebe who saw the Lidia Thorpe protest on social media, said: "I want him to talk to real traditional owners. There’s a lot of us here".

“She spoke for Aboriginal people,” he added, referring to Thorpe.

King Charles and Queen Camilla stand in front of the Sydney Harbour Bridge during a visit to the Sydney Opera House. – AP

Thorpe is renowned for high-profile protest action. When she was affirmed as a senator in 2022, she wasn’t allowed to describe the then-monarch as “the colonising Her Majesty Queen Elizabeth II”.

Albanese, who wants the country to become a republic with an Australian head of state, made an oblique reference to the issue in his speech welcoming the monarch.

“You have shown great respect for Australians, even during times when we have debated the future of our own constitutional arrangements and the nature of our relationship with the Crown,” Albanese said to the King.

But, he added, “nothing stands still.”

Dutton, who wants to keep the British king as Australia’s monarch, said that many supporters of a republic were honoured to attend a reception for the Charles and Queen Camilla at Parliament House in the capital Canberra.

“People have had haircuts, people have shined shoes, suits have been pressed and that’s just the republicans,” Dutton quipped.

But Australia’s six state government signalled their support for an Australian head of state by declining invitations to the reception. They each said they had more pressing engagements on Monday, but monarchists agreed the royals had been snubbed.

King Charles and Queen Camilla receive a traditional welcome on arriving in Canberra. – Reuters

Charles used the start of his speech to thank Canberra Indigenous elder Auntie Violet Sheridan for her traditional welcome to the king and queen.

“Let me also say how deeply I appreciated this morning’s moving Welcome to Country ceremony, which offers me the opportunity to pay my respects to the traditional owners of the lands on which we meet, the Ngunnawal people, and all First Nations peoples who have loved and cared for this continent,” Charles said.

“Throughout my life, Australia’s First Nations peoples have done me the great honour of sharing so generously their stories and cultures," Charles said.

"I can only say how much my own experience has been shaped and strengthened by such traditional wisdom.” 

Australians decided in a referendum in 1999 to retain Queen Elizabeth II as head of state. That result is widely regarded to have been the consequence of disagreement about how a president would be chosen rather than majority support for a monarch.

Albanese has ruled out holding another referendum on the subject during his current three-year term in government. But it is a possibility if his centre-left Labor Party is re-elected at elections due by May next year.

King Charles and Queen Camilla pose for a photo with students at the Sydney Opera House. – Reuters

Esther Anatolitis, co-chair of the Australian Republic Movement, which campaigns for an Australian citizen to replace the British monarch as Australia’s head of state, said while thousands turned out to see the king and Queen Camilla at their public engagements, the numbers were larger when his mother Queen Elizabeth II first visited Australia 70 years ago.

An estimated 75 per cent of Australia’s population saw the queen in person during the first visit by a reigning British monarch in 1954.

“It’s understandable that Australians would be welcoming the king and queen, we also welcome them,” Anatolitis said.

“But it doesn’t make any sense to continue to have a head of state appointed by birthright from another country.”

Anatolitis acknowledged that getting a majority of Australians in a majority of states to vote to change the constitution would be difficult. Australians haven’t changed their constitution since 1977.

“It’s tricky, isn’t it? We’ve got that hurdle, of course,” Anatolitis said.

King Charles and Queen Camilla conduct an Australian Navy fleet review aboard the naval boat Admiral Hudson in Sydney Harbour. – Reuters

Constitutional lawyer Anne Twomey said an Australian republic was not something that Charles, 75, need worry about in his lifetime.

She said the failure of a referendum last year to create an Indigenous representative body to advise government demonstrated the difficulty in changing Australia’s constitution.

“It’s just that on the whole people aren’t prepared to change the constitution,” Twomey said.

“So a republic, which would be a much more complex constitutional question than the one last year, would be far more vulnerable to a scare campaign and to opposition,” she said.

“So unless you had absolutely unanimous support across the board and a strong reason for doing it, it would fail,” she added.

Philip Benwell, national chair of the Australian Monarchist League, which wants to maintain Australia’s constitutional link to Britain, said he was standing near Thorpe at the Canberra reception when she started yelling at the king and demanding a treaty with Indigenous Australians.

“If anything, she’s helped to strengthen our support,” Benwell said.

Later in the day the royals were to take part in a Royal Australian Navy Fleet Review of five ships on Sydney Harbour.

The navy, the army, and the air force will carry out fly-pasts and more than 600 officers and sailors will conduct a "cheer ship" salute.

On Wednesday, Charles will travel to Samoa, where he will open the Commonwealth Heads of Government Meeting.