Australia's prime minister expressed his sorrow on Friday at the killing of a 15-year-old Aboriginal boy, insisting that the attack was clearly "racially motivated".

The alleged murder of Cassius Turvey in the western city of Perth has sparked outrage nationwide, with protests planned and rights activists decrying what they said was another symptom of systemic racism.

Lamenting Turvey's death as a "terrible tragedy", Prime Minister Anthony Albanese insisted "we're a better country than that, and my heart goes out to the family and the friends".

Turvey died in hospital after a man allegedly jumped out of a vehicle, chased him and hit him on the head with a metal pole.

A 21-year-old white man has been charged with murder and will appear in court next month.

The man also faces charges of aggravated assault and stealing for allegedly attacking Turvey's 13-year-old friend with a pole and taking his crutches.

Shock over the October 13 attack turned to anger after local police suggested it was too early to say whether Turvey was attacked for being Aboriginal.

Western Australian Police Commissioner Col Blanch said it might have been a "case of mistaken identity", with Turvey finding himself "in the wrong place at the wrong time".

But Albanese gave that view short shrift on Friday, stating the attack "clearly is racially motivated".

The inequalities facing Aboriginal and Torres Strait Islander people in Australia remain stark, with their life expectancies years shorter than other Australians' and their rate of deaths in custody higher.

Recent Aboriginal deaths, including many in custody, have sparked large protests, echoing the "Black Lives Matter" movement in the United States and elsewhere.