Outraged Australian women have slammed an 'offensive' census question.

The Australian census aimed at recording the country's population contains questions about age, race, religion, marital status and more.

This year, the Australian Bureau of Statistics included a question specifically for women, asking 'how many babies they had given birth to’.

Adopted, fostered and step children were not permitted in the count, with the instructions noting the answer was being recorded for fertility statistics.

There were no questions for mothers of adopted, foster, step children, or whose children were birthed via a surrogate.

This has sparked questions of insensitivity and discrimination in the census.