Pension rules mean that women who leave work to raise children receive smaller sums of cash when they retire.
Opting out of work to have a family means that many women fail to be eligible for a full state pension.
Women who retire over the next ten years will get an average £40 a week less than men from their state pension, according to new research.
Figures revealed by the Department of Work and Pensions show that women could be up to £2,000 a year worse off due to current pension rules.
Women tend to lose out on a full entitlement to a state pension because they take time out of paid work to have children. However, many men qualify for their full pension pot and, in some cases, higher Additional pension payments because they work for longer and earn more money than women.
A DWP research paper said that “median gross state pension entitlement for women reaching state pension age between 2010 and 2020 is an average of £40 a week lower than for men reaching state pension age in the same years”.
Pensions Minister Steve Webb is trying to change the system so that all men and women receive a universal pension of £140 a week in a bid to address the problem. However, the Treasury has not given the proposals the green light.
Ros Altmann, the director-general of Saga, said: “Women are more dependent on the state pension, but the state pension discriminates against women. And women who are coming up to retirement now have often not been able to build up private pensions in the way that men have”.
She added that “the best answer is to move towards a flat-rate universal pension”.
To qualify for a full state pension women have had to work for at least 39 years. However, the level is being reduced to 30 years to lessen the divide between male and female pension pay outs.
A DWP source said: “Women have been penalised by our State Pension system for too long. Steps have already been taken to fix this problem, but even women reaching state pension age in the 2030’s and 40’s are not expected to get as much state pension as men”.