WGEA director Libby Lyons said data from the agency last year showed progress on gender equality had stalled, and the new report reveals "a worrying level of apathy and indifference" towards making improvements.
"Expecting Australian women to wait a quarter of a century for the total remuneration gender pay gap to close is unacceptable. It may well take longer if employer inertia and complacency lead to a reversal of current trends," she said.
Source: Supplied/Workplace Gender Equality Agency
The data is based on nearly 5,000 reports from employers over the 12 months to 31 March 2020 and covers some 4.3 million people – more than 40 per cent of all employees in Australia.
The new projections do not reflect the impact of the COVID-19 pandemic, the effects of which Ms Lyons said would remain unclear for a few months.
Data released last month showed the gender pay gap had narrowed to 13.4 per cent in November 2020, with women working full-time still earning $242.20 less than men each week, on average.
Report author and BCEC deputy director Rebecca Cassells said if pre-pandemic trends continued, the gender pay gap among full-time executives and and senior managers would be eliminated within 10 and 15 years respectively.
But for workers in non-management roles, she said, it could take even longer.
"Some occupations may not see any change at all in their gender pay gap in the coming years," she said.
Ms Cassells said organisations that have consistently "implemented a comprehensive suite of gender equality policy and practice measures" had lower gender pay gaps and more women in senior jobs.
Ms Lyons urged all Australian employers to "act now to embed gender equality in their organisations as a standard business practice".
"Not only will it drive better company performance, productivity and profitability but it will also deliver meaningful, systemic change that will close the gender pay gap faster and make our workplaces better, fairer and safer for both women and men," she said.
The research also found the mining sector was most improved for following best gender equity practices over the last five years, while organisations in the education and training, healthcare and social assistance sectors on average showed least improvement.
Organisations that consistently audited their pay gap saw their managerial gap narrow faster than those that did not.