The analysis is contained in a series of updated fact sheets comprising statistics on family types, fertility rates, marriages, household size, cohabitation rates, divorces, and parent contact with children after separation.

Australian Institute of Family Studies Director, Anne Hollonds said the aging of the population was one key factor behind a trend that would see childless families outnumber those with children for the first time in 2030.

"ABS projections suggest that families will look very different in the next 15 years with more couple families living in smaller households without children than currently do now," Ms Hollonds said.

Key statistics include:

• There are 5,584,000 families in Australia according to the 2011 Census.
• The proportion of couples without children has increased from 28% in 1976 compared to 37.8% in 2011.
• One-parent families with dependent children have increased from 6.4% in 1976 compared to 10.6% in 2011.
• The proportion of couples with dependent children decreased from 48.4% in 1976 compared to 36.7% in 2011.
• The majority of families with children under 18 in 2012-13 were 'intact' families (73.5%).
• Step and blended families accounted for less than 6.5% of all families in 2011.
• 19.3% of families were headed by a single parent in 2011.
• In 2012, the total fertility rate in Australia was 1.93 (average number of children a woman has in her lifetime).
• In 2013, the divorce rate in Australia was 2.1 per 1,000 population.
• In 2011, the average household size was 2.6 per 1,000 population.
• In 2013, 77% of marriages took place after a couple had lived together.
• In 2013, the median age of marrying for the first time was 28 years old for women and 30 for men.