The Australian Services Union and the Australian research centre Per Capita have now drafted recommendations to the government and private sector to close the gender pay gap.
Australia has an ageing population, and research suggests that, for half of the workers, a big bump awaits on the road to retirement.
Warwick Smith is co-author of a new report into superannuation outcomes for women, entitled the Not So Super for Women report.
He says the gap between women's and men's superannuation is big.
"Women with children, mothers, have substantially lower incomes and lower superannuation balances, and men have higher superannuation balances and income. Women -- well, mothers -- work less, generally, so that's part of the explanation, but, even when we account for that and we look at full-time earnings, mothers still earn less than either fathers or women and men without children."
There are several reasons, according to surveys of Australian workers and population data collected from the Australian Bureau of Statistics.
The women were paid less than men in the same roles, their work was less stable, and they did the vast majority of unpaid housework and care of their children.
Sydney mother Lisa Smajlov has been a single mother working part-time for the past 16 years.
She points to the difficulties of saving towards retirement while raising her son.
"So I've been a single parent most of his life, and it's been sole responsibility, so I didn't receive any maintenance or any of that sort of stuff. So it's just been me and my salary and what I can bring to the table has kept us floating."
Her decision to work part-time as her son's sole parent also significantly lowered her contributions to her retirement fund.
Researchers from Per Capita, an Australian industry-research company, identified $350,000 as the minimum sum to fund a comfortable retirement in Australia.
It found that, based on income, many women have far less in the bank, so many women face the same situation Ms Smajlov depicts.
"What accommodation am I going to live in? As a renter, I haven't been able to save for a mortgage. So, you know, I don't have that stability or at least if I had nest egg, like if you sold the house and moved to a less expensive area. So that's the pipeline for me is looking at, 'Yeah, where am I going to be?' It's a big unknown, nasty question."
To answer that question for the women in her situation, the Not So Super for Women report recommends women in carer roles receive regular top-ups to super payments.
David Hetherington, a co-author of the research, says, with superannuation contributions at 9-and-a-half per cent, that would be the most effective measure to close the gap.
"Either through government, for example, on the paid parental-leave scheme, or through employers, where that's been negotiated in an EBA, for example, we think is really important on the way through."
The Australian Services Union's Linda White says her organisation will lobby the public and private sector to address the issue.
She says they will ask the federal government to consider policy through a female perspective.
"Of course, you are going to have things that have a bad effect on women if nobody's actually looking out for what's going to happen. And if we don't start doing that, we're just going to be enacting more and more policy that is just going to make retirement for women and their working lives worse and worse."
