The King has been berated by an Australian senator who told him “You are not my King” and demanded a treaty between Australia’s First Nations and its government.

Senator Lidia Thorpe waited until the end of a landmark speech Charles gave at Australia’s Parliament House, in the nation’s capital of Canberra, to verbally attack him and claim “genocide” had been committed against the Commonwealth country’s indigenous people.

Charles and Camilla have faced low-key protests during their tour of Australia, which began on Monday, from supporters of First Nations resistance to colonisation, who have been displaying a banner with the word “decolonise” at a number of events.

As Ms Thorpe was gently ushered from the hall, she shouted: “You are not our King, you are not sovereign… you have committed genocide against our people.

“Give us our land back. Give us what you stole from us… Our babies, our people. You destroyed our land.”

She continued: “Give us a treaty – we want a treaty with this country… This is not your land, this is not your land, you are not my King, you are not our King.”

The outburst from an elected representative is likely to be seen as an embarrassment for Charles, who is making his first visit to Australia as King.

Ms Thorpe sits as an independent in the upper house of the Australian parliament and issued a statement ahead of the royal visit.

“As First Peoples, we never ceded our sovereignty over this land. The Crown invaded this country, has not sought a treaty with First Peoples, and committed a genocide of our people. King Charles is not the legitimate sovereign of these lands,” she said.

“Any move towards a republic must not continue this injustice. A treaty must play a central role in establishing an independent nation. A republic without a treaty must not happen.”

She spoke to the BBC after she was removed from the parliament building, saying Charles is not sovereign because “he is not of this land”.

She told the broadcaster: “I wanted to send a clear message to the King of England that he is not the King of this country.

“He is not my King. He is not sovereign. We are sovereign. To be sovereign, you have to be of the land. He is not of this land.

“We have been demanding a treaty for decades and decades.”

It is understood the King was unruffled and did not let the outburst overshadow what the royal party viewed as a wonderful day in the Australian capital, which had seen them greet hundreds of well-wishers at the national war memorial – including a sneezing alpaca.

Earlier, hundreds of people had gathered outside Australia’s parliament house for a chance to meet the royal couple.

Australia’s prime minister, Anthony Albanese, has a long-held aim of holding a referendum on breaking ties with the British monarchy and his country becoming a republic.

But the plans were put on hold after Australians overwhelmingly rejected a plan to give greater political rights to indigenous people in a referendum held last year.

In his speech, which was overshadowed by the protest, Charles spoke affectionately about his relationship with Australia, a country he first visited as a teenager, saying he arrived as an “adolescent” and left more “chiselled” after his experience studying in the Outback.

He also highlighted the debt he owed to Australia’s indigenous people.

Charles said: “In my many visits to Australia, I have witnessed the courage and hope that have guided the nation’s long and sometimes difficult journey towards reconciliation.

“Throughout my life, Australia’s First Nations peoples have done me the great honour of sharing, so generously, their stories and cultures. I can only say how much my own experience has been shaped and strengthened by such traditional wisdom.”