What's In It For Employees?

While employees believe company-sponsored volunteer activities may be a boost to morale and workplace camaraderie, they don't view them as a way to advance their careers or develop new skills. Only 36 percent told Deloitte that volunteering can help them on the skills side, while half that amount – 18 percent – say volunteering can boost their career opportunities.

At Groupware, many employees "take it on themselves" to support causes close to them, according to Thompson, and that in itself "starts to build leadership capabilities."

Deloitte's Marshall sees wider benefits to volunteerism, especially with today's tight job market.

"As businesses continue to find new ways to retain and attract new talent, and establish a more purpose-driven and engaged workforce, they should consider how they can better incorporate volunteerism into their culture," he said in a statement. "It's a potential solution from which businesses, professionals and communities can benefit, while supporting employees' personal and career development, and boosting their sense of well-being."