Calls to return the state pension age to 60 for men and women have been rejected by the government.
The Department for Work and Pensions says lowering the age of entitlement would be “neither affordable nor fair”.
More than 69,000 people have signed a Commons petition calling for a reduction to be introduced with immediate effect.
The age threshold was increased to 66 for everyone last year with further phased increases to age 68 planned.
Until 2010, the state pension age was 60 for women and 65 for men, but qualifying ages were brought in line for everyone by 2018 and have been rising since.
In 2020, a further change to the rules required men and women born between 6 October, 1954, and 5 April, 1960, to have to wait until their 66th birthday to receive their pension.
Campaigners say the coronavirus pandemic has put a renewed focus on intergenerational fairness, with many young people losing their jobs and struggling to find work.
They say the balance needs to brought “back in to young people’s favour” to help “restore their future”.
And they want older people to be allowed to retire earlier, to free up employment for younger workers.
While there would be a financial cost to the Treasury, they say paying pension benefits earlier would be “more positive” than having to top young people up with Universal Credit.
The Department for Work and Pensions (DWP) says lowering the state pension age to 60 would place an unaffordable and unfair burden on taxpayers.
It would also make the benefit unsustainable in the long term, the department argues in its response to the petition.
The number of people over state pension age compared to the working population is expected to increase because, on average, people are living longer, according to the Office for National Statistics.
Had the state pension age not risen for men and women, “the total additional cost to taxpayers would have been around £215bn for the period 2010/11 to 2025/26, in 2018/19 prices,” the DWP said.
It added that ministers have provided “an unprecedented amount of support via our plan for jobs to help those of all ages find work and get the skills they need to return to work”.
Petitions on the UK Parliament are considered for debate by MPs when they reach 100,000 signatures.
They can raise awareness about issues and help put pressure on the government, but their results are not binding.