Women's contributions to occupational pension schemes fell over the last year despite average contributions rising in line with inflation.
Women's average monthly contributions fell 5% to £200 a month, according to the Friends Life Workplace Savings Index.
This was 38% lower than men's average of contribution of £324, Friends Life says.
Average contributions for women under 30 decreased by £2 to £128 a month, women aged 30-45 saw a £1 decrease to £213 a month and women aged 60 or more saw a £2 decrease to £193 a month.
Women in the 45-60 age group saw an increase in average pension contributions, but this was lower than for men of the same age.
The report found that men increased average contributions by £14 to £324 a month, with men aged 45 to 60 making the largest average increase of £19, bringing average monthly contributions to £383.
Martin Palmer, head of corporate benefits marketing at Friends Life, said: "To beat the savings crisis customers will need to make larger increases year-on-year to ensure their savings can support them financially in retirement."
The workplace savings index will be compiled quarterly by DCisions, based on data from workplace pension schemes run by Friends Life, encompassing more than 20,000 UK organisations.
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