The Australian Institute of Superannuation Trustees (AIST) has called for action on reducing the superannuation gap women currently face and has proposed a bonus for women who take unpaid maternity leave.

"We need to have policies in place that address the issue," AIST chief executive Fiona Reynolds told Investor Weekly.

"We have made the case for a super component to paid parental leave for some time, but not everyone takes paid parental leave.

"That's why we would like to see a super payment as part of the baby bonus."

Although Reynolds said she recognised that would be a relatively small contribution, any super contribution was better than none.

AIST also said a return-to-work super bonus after a career break could go some way to addressing the issue.

New research by the Australian Centre for Financial Studies (ACFS) for AIST found women's super balances in 2010 still showed a 'flat-lining' between the age groups of 38-42 and 43-47, which was also apparent in previous years.

The report analysed the latest data from the Household, Income, Labour and Dynamics in Australia Survey, which is a longitudinal survey of around 20,000 Australians.

"There's a clear flat-lining of women's super that has remained unchanged for almost a decade," Reynolds said.

"The super gender gap is still as large today as it was in 2002 because women are still spending five to six years out of paid work to raise children and they still earn, on average, nearly 20 per cent less than men."

The study indicated the average super balance (2010) for men in the workforce between the ages of 58 and 62 was about $210,000 for men, compared to $95,000 for women.

That ratio of around double does not appear to have changed much since the 2002 survey.

Reynolds said in the past some women made use of the co-contribution scheme offered by the government to top up their super, but the survey found the rate had dropped off since the global financial crisis (GFC).

About 75 per cent of employees surveyed were not contributing anything extra to their fund, the survey found.

"Post GFC, the number of people making voluntary contributions to their super has declined a little, which is concerning," Reynolds said.

"It's important that the industry moves to reassure members, restore confidence and works further on incentives to save through super, because we know it's in members' long-term interest."

She said a potential solution to the existing gender gap could be a more targeted form of co-contribution, which would allow women on parental leave to contribute more to their super balance.

Another finding of the survey was that Australians valued a high super balance more than a rise in the value of their houses.

"When assessing their own financial position, individuals report that higher super balances had approximately twice the effect of an equivalent increase in the value of home equity," ACFS research director Kevin Davis said.

"This supports the findings of recent research by ME Bank, suggesting that housing wealth is not generally seen as available for increasing consumption either because 'downsizing' is not attractive, or because of bequest motives.

"An increase in superannuation balances also had a stronger impact on financial wellbeing than does an equivalent rise in income."