The proposal that people should work beyond 65 in return for a higher state pension has been criticised by a pensioner lobby group.
Working longer may not be for everyone
The National Pensioners Convention (NPC) branded the government's Pensions Commission proposal to raise the state pension age "unfair".
Later retirement would hurt manual workers who generally have a shorter life expectancy, the NPC said.
Earlier, the pensions minister said a rise in the pension age was likely.
"Raising the state pension age would punish manual workers unduly, since they do not live as long as people in white collar jobs," Neil Duncan-Jordan, spokesman for the NPC said.
Mr Duncan-Jordan added that increased longevity - the reason cited by the Pensions Commission for raising the pension age - was a double edged sword.
"It is all very well living to 85 but many people endure prolonged ill health in the last decade of their lives," he said. "If they work later this cuts down the time they have to enjoy a third age."
The NPC, which holds an annual "pensioners' parliament" in Blackpool, has repeatedly called for a sharp rise in state pension payments.
The state pension age for women is already set to rise from 60 to 65, the same as for men, between 2010 and 2020.
Last year the Pensions Commission, led by Lord Turner, proposed that people should work even longer before being able to claim the state pension.
However his suggestion was that a further increase from 65 to 66 - or even higher - should only be phased in from 2030.
In a speech to the Work Foundation last week, Work and Pensions Security John Hutton said that a rise in the state pension age was "inevitable".
The government will publish a white paper on pensions in the spring.