Hundreds of people demonstrated in Australia's major cities on Saturday to protest the deaths of Indigenous people in custody, ahead of the 30th anniversary of a major report into the issue.

More than 470 Aboriginal people have died in custody in those three decades, including at least five since last month, local media reported.

"Almost 30 years and 441 deaths since the Royal Commission, no police officer or authority has been convicted for Black deaths in custody," said NATSILS, a legal services group for Aboriginal and Torres Strait Islander people. 

"Our people continue to die at horrific rates. There is no accountability, and no justice," it said in a statement. "We call on the Prime Minister to meet us face to face on the 30-year anniversary to hear our stories, to see our pain, but most of all we want answers."

Protests and marches took place in cities including Sydney, Brisbane, Melbourne, and the capital Canberra ahead of Thursday's anniversary of the report by a royal commission on Black deaths in custody.