Volunteering charity Community Service Volunteers is urging the Government to increase the involvement of volunteers in social care services.
The Government is expected to publish a green paper this week outlining how it plans to cope with an ageing population and the resulting demands on services.
The cost of social care is expected to rise to £24bn by 2026, according to CSV, but it said increasing the role of volunteers could be an economically effective way of improving services.
The charity said volunteers could have a positive impact on service users' wellbeing and using them was an option that should be exploited by service commissioners.
Dame Elisabeth Hoodless, executive director of CSV, said: "The Government has promised a radical rethink of the care system. That new approach must include volunteers who play a vital but underestimated role in boosting the quality of life for the people they support."