Population figures released on Wednesday by the Australian Bureau of Statistics revealed the Aboriginal and Torres Strait Islander population had increased by nearly a quarter in the past five years.

In the five years to June 2021, the Indigenous population grew 23.2 per cent from 798,000 to 984,000.

The population represents about 3.8 per cent of the total Australian population.

The bureau's demography director Emily Walter said the increase in the Indigenous population outstripped the growth among non-Indigenous people.

"(The 23.2 per cent growth) is higher than the 5.5 per cent increase for the non-Indigenous population over the same period," she said.

"We have seen similar increases in the Aboriginal and Torres Strait Islander population between past censuses, and they are partly explained by changing identification over time."

Of the nearly one million Indigenous Australians, one-third of them were under 15 years old, while 5.4 per cent were over 65.

Comparatively, almost 18 per cent of non-Indigenous people were under 15 while 17.2 per cent were over 65.

"This younger age structure is the result of more babies being born and people dying younger in the Aboriginal and Torres Strait Islander population compared with that of the non-Indigenous population," Ms Walter said.

While the proportion of Indigenous Australians among different age groups were largely the same between men and women, the population data showed there were slightly more males to females.

Among Indigenous people there are 101 men for every 100 women but women outnumbered men in age groups over 35 years old.

NSW had the largest Indigenous population of any jurisdiction, with 339,500 people, followed by Queensland with 273,200 and WA with 120,000.

The top three states made up almost three-quarters of the total Indigenous population in Australia.

While Victoria had the fastest growing increase for its Indigenous population, increasing by 36.2 per cent in the five-year period, it still has the lowest proportion of Aboriginal and Torres Strait Islanders (1.2 per cent).

Australian Associated Press