Women on the full age pension will be hit hardest if the Abbott government changes the way the payment is indexed.
The Coalition is considering pegging the age pension to the rise in prices rather than to the faster-growing male earnings.
If the government makes the change in the May 13 federal budget, it will disadvantage all age pensioners as male earnings outpace inflation by about 1.5 percentage points a year, says Michael Rice, an actuary and chief executive of Rice Warner.
Pegging the age pension to inflation would disadvantage more women than men as almost 60 per cent of those on the full age pension were women, Mr Rice said.
Women have less superannuation than men because they take time off to raise children, and face pay discrimination.
Women also live longer than men and so have longer retirements to fund.
Changing the indexation rate would bring immediate savings for a government that wants to cut spending.
The Howard government changed the indexation of the age pension from inflation to male wages in 1996.
"If the age pension had been indexed to changes in the CPI [inflation] from 2000 to now, the age pension for a single person would be about $7000 a year less," said Pauline Vamos, the chief executive of the Association of Superannuation Funds of Australia.
"Over the past four years, CPI indexation alone would have resulted in the annual single age pension being around $2000 less," she said.
The government is also considering lifting the access age for the age pension to 70.
The pension age is already scheduled to increase. It is 65 for most people now and will start increasing in 2017 to reach 67 for everyone by July 1, 2023.