Charities are to campaign to get volunteers included in anti-ageism legislation planned by the Government.
The Government is due to consult on an EU directive on equal treatment for employees at the beginning of next year and a key part of the subsequent legislation will cover ageism.
"We want the new law to cover volunteers as well as employees because there is a big problem with discrimination against older volunteers,
said a spokeswoman for Age Concern England, which organised a seminar on the issue last week attended by voluntary-sector representatives.
Although ageism in the voluntary sector is an under-researched issue, there is evidence that older volunteers do suffer unfair treatment, according to Age Concern.
"Much time and money is spent promoting volunteering to younger people and organisations often operate upper age limits,
said the spokeswoman.
Findings from the Institute for Volunteering Research suggest that volunteers aged over 50 were under represented in voluntary activity compared with people in their thirties and forties.
Denise Murphy, director of the retired and senior volunteer programme at volunteering charity CSV, agreed that older volunteers often face discrimination.
"I've had many letters from volunteers who are suddenly told, at the age of 70 or even 65, that they are no longer wanted and they find it very distressing."
One of the reasons some organisations give for not using older people is difficulty in insuring them.
But Murphy believes this problem is over stated: "We have many volunteers in their seventies and eighties and have not had trouble getting insurance for them."
She added that older people may have to change their volunteering roles but that organisations which practised discrimination were missing out on a valuable pool of talent.
Age Concern is planning another meeting later this year to bring together charities and formulate a united response to the government consultation.