Across the country, smouldering eucalyptus leaf smoke settled on thousands of Australians mourning the death of a 15-year-old First Nations boy Cassius Turvey.

“How many children do we have to send to the grave?” Wiradjuri elder Jenny Munro said at a vigil in Sydney on Wednesday evening, the crowd heavy with candles and grief.

“We’ve lost so many children in a battle they aren’t even prepared for.”

Hundreds gathered outside the Sydney Town Hall, and at more than 40 rallies and vigils held across Australia on Wednesday.

The Indigenous boy’s mother led the march through Perth’s CBD calling for “change in the name of Cassius”.

Cassius died in hospital in October, 10 days after he was allegedly beaten with a metal pole while walking home from school in his uniform.

“That boy represented our hopes, our dreams, our future and they took it from us,” Gumbaynggirr Dunghutti Bundjalung woman Elizabeth Jarrett told the vigil in Sydney.

“He represents every single son, every brother, right across this vast continent. And we won’t ever forget it.”

Wiradjuri teenager Ethan Lyons also spoke at the Sydney memorial.

“We remind this nation that we are young and full of life, like Cassius,” the student, still in his school uniform, told the crowd.

“But we also remind them that young people are watching, we watch the white supremacy that runs deep in this country.”

A statement from Cassius’ mother was read out at Wednesday’s vigils.

“I don’t want any more violence … I want calm and peace,” Mechelle Turvey said.

“I don’t want to fuel prejudices, biases. I don’t want to fuel stereotypes of First Nations people as violent.

“The answer I want is why?”

Friends and family have described Cassius as a “teddy bear” with an infectious smile who was “larger than life”.

More than 40 events honouring Cassius have been scheduled in coming days, including gatherings in the United States and New Zealand.

Jack Steven James Brearley, 21, has been charged with his murder and is due to face a Perth court on November 9.

-AAP