More than 40 per cent of working age adults are unaware of future changes in women's state pension age.
From 2010, a higher pension age for women will be phased in, and by 2020 it will be age 65, the same as it is for men.
Research from the Department for Work and Pensions (DWP) questioned about 2,700 adults of working age. Its findings will contribute to the design of the department's forthcoming campaign on the future equalisation of the state pension age.
Only 43 per cent of women who will be affected by the increase - those born after April 1955 - knew their own state pension age. Of these, knowledge was lowest among women more likely to have to rely on the state pension in retirement - for example, those without a private pension, and non-working women.
Awareness levels also differed greatly by age, with older respondents being much more likely to know about the changes - which is unsurprising, given their proximity to retirement.
Whether respondents had any private pension provision was also closely linked to their level of awareness. Nearly three-quarters (71 per cent) of those who had a private scheme said they were aware of the changes, in contrast to 43 per cent of those who had never had a private pension.
The report recommends the DWP should target specific groups - younger people, the unemployed, workers in intermediate or routine occupation types, and women who will be affected - as a priority on the equalisation of the state pension age.
Last week, the DWP Pensions Age Taskforce met for the last time in an attempt to decide whether or not to increase the state retirement age.