Australians may think of themselves as an egalitarian society, but research shows inequality has increased over recent decades.

Some of the fastest income growth among developed nations in recent years has been in Australia, but it was not evenly spread, a new book from the Australian Academy of Science says.

The book cites OECD figures that show rich people in Australia had the fastest growing incomes between 1985 and 2008.

According to the book, "Negotiating our future: Living scenarios for Australia to 2050", the nation's poorest had the second fastest income growth and middle income earners come last.

One measure of inequality is income ratio between the wealthiest and poorest 10 per cent of the population.

The book includes graphs that show between 1985 and 2008 Australian incomes for the top decile rose at 4.5 per cent per year, the bottom decile was at 3.6 per cent and for the total population it was 3.0 per cent, indicating a relatively slower growth in mid-range incomes.

Indigenous Australians still suffer chronic disadvantage, making it hard to justify the egalitarian tag, the book says.

Inequality and inequity are just two of a raft of problems identified in the book "Negotiating our future: Living scenarios for Australia to 2050".

The book does not provide a solution but proposes tools, models and approaches that could be used to ensure Australia's social, economic and environmental sustainability to 2050 and beyond.

"The future will not take care of itself," the authors say.