Royals back in Sydney for final day

King Charles III and Queen Camilla will carry out a final round of events in Sydney, after an at-times fiery visit to Australia's capital Canberra, as the royal tour wraps up.

Their Majesties will attend a community barbecue in Sydney's west hosted by New South Wales Premier Chris Minns, ahead of a meet and greet with well-wishers in front of the Sydney Opera House on Tuesday afternoon.

The last time a sovereign met the crowds at the Opera House was when the late Queen Elizabeth II visited in 2006.

The couple will then participate in a Royal Australian Navy Fleet Review of five ships on Sydney Harbour.

The Navy, the Australian Army, and the Royal Australian Air Force will conduct fly-pasts and more than 600 officers and sailors will conduct a 'cheer ship' salute.

In the morning, the King and Queen will split up for separate engagements.

Charles will visit the National Centre of Indigenous Excellence while Camilla will visit Refettorio OzHarvest and Green Square Library in the inner city.

Later, the King will visit the Melanoma Institute where he will meet joint Australians of the Year Georgina Long and Richard Scolyer.

The 75-year-old was earlier this year diagnosed with a form of cancer, the type of which has not been officially confirmed.

The final day of events for the royal couple comes after Victorian Senator Lidia Thorpe interrupted a reception at Parliament House in Canberra on Monday to protest the monarchy.

"You are not our king. You are not sovereign," the Indigenous senator said before being led away by officials.

"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," she said before being removed.

While in Canberra, the King also laid a wreath at the Australian War Memorial and planted a gum tree at the Botanic Gardens.

He met with volunteer firefighters and researchers at the CSIRO bushfire behaviour lab, witnessing a demonstration of how quickly bushfires can spread and learning about suppression methods.

The Queen attended a roundtable discussion about domestic and family violence while the King met with Prime Minister Anthony Albanese and Opposition Leader Peter Dutton.

Following events in Sydney, the King and Queen travel to Samoa to open the annual Commonwealth Heads of Government Meeting.

Senator 'disrespectful'

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 told Nine's Today programme on Tuesday. 

"But it didn't put a dampener on ... the very positive rest of the welcome ceremony, which I think was really very positive."

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 told Nine.

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