Economist Preston Tsamassiros uses a "domestic work" and "market work" index that shows what more equal parental leave can achieve for families trying to juggle new family responsibilities and careers.

A long-term transfer of household chores from mothers to fathers, amounting to three hours a week or a staggering 20 days of full-time work a year, occurs in households that can get paternity leave.

There is also a more equal split of paid work over the decade following any paternity leave, he told a two-day Women in Economics Network conference on Thursday.

"We're talking about 12 days of leave - if that can have a significant and really long-lasting effect on the amount of domestic work that fathers do, it's a pretty compelling justification for enacting policy," he said.

Currently, it's not straightforward for fathers who want to care for a newborn.

"A lot of men don't have access to any specific paternity leave, or they have access to a very limited amount," he said.

So, in practice, many take annual leave, unpaid leave, long service leave.

New fathers who take a longer period of leave have an even greater impact on household "specialisation" in the longer term, permanently changing the balance of paid and unpaid work.

Owain Emslie, a senior associate at the Grattan Institute, said the evidence supported the case for more gender equal parental leave policy to support fathers taking leave.

There were also social, health, child development, relationship and economic benefits to be had, including gains for women's economic security and an overall GDP impact, he said.

"All of those largely rely on there being a lasting behaviour change in the split of labour in a couple."

The huge national data set known as HILDA (Household, Income and Labour Dynamics in Australia) shows there are still very few households where the main breadwinners are women.

Australian Associated Press