Australians born of Australian parents will soon be a minority.

The census shows Australia reached a "tipping point" in 2016 where only slightly more than half its residents had two Australian-born parents.

The long-term low of 50.7 per cent is a step down from 54 per cent in 2011 and 57 per cent in 2006.

More than a quarter of Australia's population in 2016 was born overseas (26.3 per cent, up from 24.6 per cent) and for the first time since colonisation, most of the overseas-born came from Asia rather than Europe.