Women without the shackles of dependent children are more likely to be the main breadwinners in their household, a major study shows.

But women with dependent children continue to do the lioness' share of housework, slaving an average of 15 hours more on housework and 15 hours more on child-rearing than men.

These insights into the home life of Australians come from the Household Income and Labour Dynamics in Australia study (known as HILDA) by the University of Melbourne and edited by Associate Professor Roger Wilkins. It is Australia's only large-scale longitudinal household study.

''It is absolutely true that the decision to have children has big impacts on women's employment and earnings – big negative impacts,'' Professor Wilkins said.

''I would like to think most women know that their labour-market fortunes are going to take a hit from having children, but is the hit bigger than they expected or bigger than it should be? Possibly yes,'' he said.