About 100,000 families have used paid parental leave in its first year.
Yesterday marked the first anniversary of the scheme, which pays parents about $590 a week for 18 weeks to help them with the costs of having a child.
''Half the mothers who have so far received paid parental leave earned less than $42,000 in the year before their baby was born or adopted,'' the Minister for Families and Community Services, Jenny Macklin, said.
''This shows how important paid parental leave is for supporting women on low incomes, many of whom would not have access to paid parental leave through their employer.''
About 72,000 people are either still receiving or have already received the leave payment.
Although paid parental leave started on January 1, people were able to register for it from October 1 last year. The leave is paid to eligible working parents.
Almost all the claimants have been women, with an average age of 31. Most had partners and 73 per cent lived in a major city.
The scheme will be extended on January 1, 2013, to provide an additional two weeks' pay to fathers and other partners. People will be able to register for the new payment from October 1 next year.