Industry Super Australia (ISA) released analysis showing more than 467,000 NSW mothers had received the Commonwealth's Parental Leave Pay in the past decade.

But the government does not pay the super guarantee on the scheme, and so unless an employer voluntarily pays super on the leave, working mothers' savings are falling behind, ISA says.

Minister for Superannuation Jane Hume says the government is "focused on improving retirement outcomes for women by increasing superannuation coverage" and making the system fairer for women and all Australians.

ISA, which has major funds Australian Super, HostPlus, HESTA and Cbus among its 13 members, says the "hidden super sting" in the parent leave scheme could cost a mother of two $14,000 from her final retirement savings.

Overwhelmingly it was women who were missing out, with 99.5 per cent of Parental Leave Pay applicants in NSW being female, the ISA reports.

The Parkes electorate had 8950 female applicants to the Commonwealth Parental Leave Pay from January 2011 to June 2020, who together missed out on $10 million in super contributions, the analysis provided by the ISA of Department of Social Services data shows.

In comparison, the electorate had 50 male applicants to the scheme, who together had $100,000 in lost super, the analysis shows.

The modest payment of super linked to the Commonwealth's 18-week paid parental leave scheme, paid at minimum wage and available to most working mothers, was an important equity measure to ensure women's savings kept pace, the ISA says.

"NSW women are being made to sacrifice their retirement savings to have children," ISA advocacy director Georgia Brumby said.

"It's hard enough trying to juggle work and raising a family - it's not fair that thousands of women are also missing out on thousands from their super as well."

"The Prime Minister should take the opportunity to fix this glaring inequity and make a positive step towards ending the gender super gap - otherwise we will continue to see too many women at risk of retiring into poverty."

Ms Hume, a Liberal senator from Victoria, reported of the government's efforts to improve the scheme for women.

"The Morrison government made reforms to the paid parental leave scheme in 2020 to enhance its flexibility and allow Australian families to choose how to use parental leave between primary and secondary carers," she said.

"Given the disruptions to Australia's workforce due to COVID-19, we have not seen the full impact of these reforms since they were proclaimed.

"It would be remiss of this government to make further changes without proper consideration of the changes already made.

"We are focused on improving retirement outcomes for women by increasing superannuation coverage and making our system fairer for women and all Australians."