An Aboriginal protester has been arrested at the Sydney Opera House as crowds await a glimpse of the King and Queen on the final day of their tour in Australia.

Throngs of people have packed the harbourside forecourt, where the royal couple are due to visit on Tuesday afternoon.

Wayne Wharton, a prominent Indigenous activist from Brisbane, was arrested after shouting anti-monarchist slogans and refusing a police order to move on.

It comes as backlash over an Aboriginal senator’s heckling of King Charles in Canberra on Monday intensifies, with politicians and some Indigenous leaders condemning Lidia Thorpe’s behaviour.

Mr Wharton had shouted “he’s not my King”, echoing the words of Thorpe the day before.

The crowd waiting for the royals – many clutching mini union jack flags – shouted back “God save the King”.

Mr Wharton had also protested outside the church service the royals attended on Sunday.

When the Kooma man was arrested and placed into a police van on Tuesday, the gathered crowd applauded officers.

Many of the hundreds there had been queuing since early on Tuesday, a few draped in British flags. Others had accessorised with royal-themed jewellery and handbags.

“We want to celebrate our country and all the people in it,” says Karen Clark, with her little boys Benjamin and Harrison who were both wearing crowns and capes with a fake fur trim.

“We were brought up with the King, we celebrate the King’s birthday with the boys – it’s fun to have high tea and dress up in our best outfits.”

“My father was from Liverpool and I’ve always been interested in the Royals,” says Bettina Bethuel who came with her friend Taja Shephard.

Taja saw the heckling by Thorpe on TV and wasn’t impressed.

“Ï thought it was a little rude but I suppose she makes her point for Indigenous people,” she said. “But I don’t think it’s appropriate how she behaved.”

On the other side of the city on Tuesday, King Charles visited the National Centre of Indigenous Excellence in Redfern, where he met with Aboriginal elders.

The independent senator’s protest has been praised by some Indigenous activists as brave, but condemned by other prominent Aboriginal Australians as “embarrassing” and disrespectful.

It has also been roundly criticised by her parliamentary peers.