The retirement age for women increased from 60 to 65 to be aligned with men's last year, and will rise to 66 by 2020.
In 2016, the department for Work and Pensions (DWP) estimated that undoing state pension age increases for women would cost £77bn.
However, an update to its previous analysis has found that this figure has increased 136 per cent to hit £181.4bn, over the period 2010/11 to 2025/26.
Coupled with the costs of reversing changes to mens' state pension age this figure increases to £215bn.
The increase in costs is because the new £181.4bn figure covers the time period 2010/11 to 2025/26, whereas the previous £77bn figure covered the time period 2010/11 to 2020/21.
The £77bn figure was also calculated before the new state pension was introduced.
Under the new state pension, announced in 2014, pensioners receive approximately £150 a week or more if they have paid 35 years of full-rate national insurance contributions, compared to the previous threshold of 30 years.
Total cost estimate of reversing the state pension age changes:
£bn | Women | Men | Total |
State pension | 188.4 | 17.6 | 206 |
Other pensioner benefits | 9.9 | 19.4 | 29.3 |
Working age benefits | -16.9 | -3.2 | -20.1 |
Total | 181.4 | 33.8 | 215.2 |
Tom Selby, senior analyst at AJ Bell, said: "These astronomical costs are the central reason government continues to resist campaigners who argue they were not adequately informed of the changes to their state pension age.
"Paying out over £180bn to women affected by the increase in their state pension age would blow a colossal hole in the nation’s finances which would need to be plugged.
"The danger is that the burden would fall on younger generations through higher taxes or an even longer wait to receive the state pension – or a combination of the two.
"Whatever the rights and wrongs of the case – and it is clear communications about the state pension age hike left something to be desired – the result should not be a transfer of wealth from millennials to Baby Boomers."
Plans to increase the state pension age were first announced in the Pension Act 1995 but these changes were accelerated as part of the Pension Act 2011.
Campaign groups The Women Against State Pension Inequality (Waspi) and Backto60 have claimed these changes were implemented unfairly, with little or no personal notice.
The groups, which are calling for compensation for those affected, have also claimed that changes were implemented faster than promised with the 2011 Pension Act and left women with no time to make alternative plans, leading to devastating consequences.
This week (June 5 and 6) Backto60 took the government to the High Court for a judicial review into the way the retirement age was raised.
