The gender pay gap is so large at almost 15% that women will effectively work the rest of the year for free, it is claimed.
A study by the campaign group Fawcett Society suggests that, rather than improving, the pay and jobs prospects of women are going into reverse amid the Government's austerity measures.
Chief executive Ceri Goddard said: "At the same time, women's unemployment stands at a 24-year high and growing numbers of women have been forced into low paid, part-time and insecure employment - underemployment.
"Far from slowly moving forward, we now face going into reverse. If Government wants to avoid an unprecedented backwards step on its watch, they must take more action."
The conclusions were released as separate research for the Chartered Management Institute (CMI (BSE: CMI.BO - news) ) found the average female company executive earns more than £400,000 less than a male counterpart over her career.
According to the institute, the average gender pay gap for UK executives is more than £10,000 annually.
It also claimed that women receive less than half the bonus payments given to men and 4.3% of female executives were made redundant in the past year, 1.1 percentage points more than male bosses.
It found that, while women now make up 57% of company executives, only 40% are departmental heads and fewer than one in four are chief executives.
The survey of more than 38,000 executives revealed a "substantial" gender pay gap at the higher end of the executive career ladder, the institute said.
"A lot of businesses have been focused on getting more women on boards but we've still got a lot to do on equal pay and equal representation in top executive roles," said CMI chief executive Ann Francke.
"Women make up almost three out of four at the bottom of the ladder but only one out of four at the top."