Low pay and poor pension provision mean that voluntary and community workers - many of whom dedicate a lifetime to helping others - face a retirement in poverty, the Unison union warned yesterday.
The public-sector union said a survey of 2,000 of its members in the third sector shows many cannot afford to be in a pension scheme, even if a decent one is available.
The union found that four out of five employers have workplace pensions but two out of five workers surveyed are not involved in the schemes.
It is concerned that when auto-enrolment into pension schemes comes in later this year a large number of workers will opt out because they can't afford contributions.
This is a new mandatory scheme, in which employers will have to provide an occupational pension at a certain level. All staff will be opted into the scheme but if they wanted to opt out, they could do so.
But the minimum level of employer contributions have been set at a very low level and the pension is not guaranteed. The member, not the employer, bears all of the risk from investments.
Unison national officer for community and voluntary-sector workers Simon Watson said: "There is a very real danger that after many years of working to help others, third-sector workers will find themselves struggling to keep out of poverty in their retirement.
"It is vital that we get the message over to both employers and workers that a decent pension scheme means the difference between dignity in retirement and just scraping through by relying on state benefits."