Middle-class Australians are being squeezed into lower incomes or absolute poverty at some of the fastest rates in the developed world, according to a new international report that warns of the growing threats from job automation.

Ahead of an election campaign that will be dominated by appeals to a "fair go" and "equality", a report from the OECD released on Thursday said high-income earners in Australia were grabbing a larger share of national income, leaving less for the rest.

A new OECD report has found the world's middle income earners, including those in Australia, are being squeezed Credit:James Alcock

Australia is one of four rich nations - including Britain, the US and the Netherlands - where there has been a "significant fall" in the number of people on middle and upper-middle incomes.

Middle income is defined in Australia as those households earning between $US19,537 and $US52,097 in purchasing power parity dollars.