More than a million women are worse off by an average of around £32 a week as a result of the increase in the state pension age, analysis by economists has found.
The Institute for Fiscal Studies (IFS) found that the increase in the state pension age for women from 60 to 63 between 2010 and 2016 was saving the Government billions, but hitting the household incomes of women affected.
Although the increase in the state pension age had boosted employment, as more women stayed in work, the extra wages only partially offset the potential pension income they would have received.
Some 1.1 million fewer women are receiving a state pension as a result of the age increase and the Government is spending £4.2 billion a year less through pension and other benefits payments.
Affected households are receiving around £74 a week less in pension and other benefits as a result.
But employment rates among the group have substantially increased, boosting their gross earnings by a total of £2.5 billion - and providing a further £0.9 billion of tax revenue for the Government.
The IFS report said: "Overall, we find that increasing the state pension age from 60 to 63 reduces the net household income of women aged 60 to 62 by an average of £32 per week, with an increase in earned income partially, but not entirely, offsetting the loss of state pension income.
"After accounting for behavioural change, we find that the public finances are strengthened by an estimated £5.1 billion per year, of which £4.2 billion comes from lower benefit payments (net of tax, where applicable) and £0.9 billion from higher direct tax payments elsewhere."
IFS senior research economist Jonathan Cribb, one of the authors of the new report, said: "The tax and benefit system is much more generous to those above the state pension age than those below it.
"So while increasing the state pension age is a coherent response to the public finance challenge posed by rising longevity, it does place a further pressure on household budgets.
"The increased state pension age is boosting employment – and therefore earnings – of affected women, but this is only partially offsetting reduced incomes from state pensions and other benefits.
"Since both rich and poor women are losing out by, on average, roughly similar amounts, the reform increases income poverty rates among households containing a woman who has reached age 60 but has not yet reached her state pension age.
"More encouragingly, we find no evidence of increases in other measures of material deprivation. It is important that the Government communicates the ongoing increases in the state pension age clearly so that families can plan for their retirement as well as possible."
A Department for Work and Pensions spokesman said: "The decision to equalise and increase the state pension age is both fair and sustainable for future generations and in line with continuing rises in life expectancy.
"Women retiring today can still expect to receive the state pension for over 24.5 years on average – which is more than any generation before them and several years longer than men. By 2030, more than three million women stand to gain an average of £550 extra per year as a result of the new state pension."