Independent senator Lidia Thorpe's protest at a reception for King Charles III was "grandstanding" and "failed miserably", according to frontbenchers on both sides of parliament.

But on Q+A on Monday night, one First Nations man challenged politicians to listen to her message, asking in the wake of the failed Voice referendum: "What do Indigenous people have left?"

"After the recent history, or the last year at least, how can we find this audience with the monarch, in particular, to effect that change," said Daniel Williams during a taping of Q+A at the Brisbane Powerhouse.

"Throughout last year's Indigenous Voice referendum, the monarchy provided no comment toward the proposal, Indigenous self-determination, or the effects of colonialism linked to their lineage."

Senator Thorpe was escorted out of Parliament House's Great Hall after yelling "you are not our king" and "this is not your land" to King Charles and Queen Camilla, who sat a few metres away with Prime Minister Anthony Albanese.

"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," said Senator Thorpe, who is Gunnai, Gunditjmara and Djab Wurrung.

Mr Williams, a descendant of the Gureng Gureng people in Bundaberg and the Meriam Mer people of the Eastern Torres Strait, asked the panel what their position was on the "repatriation of Indigenous remains and return of artefacts to country".

"I do believe it was an important issue, still affecting Indigenous Australians. We're talking about 200 years of pain that is continuing to be unanswered and unresolved," he said.

Employment Minister Murray Watt and opposition frontbencher Susan McDonald offered to take the issue up — but both argued Senator Thorpe had done her cause no favours.

"We had the opportunity to have a forum to showcase Australia's parliament. We had a lot of people who've really contributed to Australia in a whole lot of ways, and they were there and should have had the opportunity to talk about their issues."

Senator Watt told Q+A he was "not aware until this very moment that this is the issue that Lydia was raising today".

"I don't think it worked. I don't think it got the message through to anyone in the room," he said.

"If the idea was to raise the issue with the people who were in the room, I think it failed miserably."

Senator Thorpe was elected to the Senate on a Greens ticket but quit last year over the party's support for the Voice.

On Q+A, Queensland Greens senator Larissa Waters said she was "not going to police the actions" of her former party colleague.

She said she "chose not to attend the ceremony" because she supports Australia becoming a republic.

"I think Australia is a mature nation now and I would like to see us have our own head of state," Senator Waters said.

"I think that's also a chance for us to have that deeper conversation, and to acknowledge First Nations owners of the land, and to have treaty and treaties and truth-telling."

But Mr Williams questioned whether Senator Waters' no-show sent a strong enough message.

"If we want to take this approach [of] not attending the meetings or not attending these events and what-not, then it doesn't get talked about at all," he said.

"I wouldn't be asking these questions or bringing it to the [program]."

In a statement after the protest, Senator Thorpe said she was attempting to hand the king a "notice of complicity in Aboriginal Genocide" according to the Statute of the International Criminal Court 1998.

"Today I was silenced and removed from the parliamentary reception when pointing out that the Crown stole from First Peoples," she said.

"The truth is, this colony is built on stolen land, stolen wealth and stolen lives.

"The British Crown committed heinous crimes against the First Peoples of this country. These crimes include war crimes, crimes against humanity and failure to prevent genocide. There has been no justice for these crimes. The Crown must be held accountable."

In his speech, the king acknowledged the First Australians and "how much my own experience has been shaped and strengthened by such traditional wisdom".

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

The king also did not acknowledge Thorpe's disruption, which has made headlines in Britain and around the world.

Watch the full episode of Q+A on ABC iview.