"The changing demographic of our society is good for the sector," she says. "But I question whether the sector is thinking enough about the issues it creates."
Berry, who is 60, uses herself as an example of changing work patterns. After many years working as a sector chief executive, she decided that she wanted more freedom and variety and "went portfolio" a few years ago. Along with chairing the Commission on Ageing and the Voluntary Sector, she is deputy chair of the Canal and River Trust, a visiting fellow at Cass Business School and an associate of Civil Exchange, a think tank that tries to help civil society and government work better together.
She believes many skilled employees spend the first part of their career building a reputation, the middle part staying in the same role for a long period and the third part in a "third age of employment", when they do a variety of jobs part-time. "Maybe we're going to have a sort of post-employment group of portfolio workers," she says.
Berry expects this changing charity workforce to be drawn from a growing group of people who are retired for up to 20 years and constitute a valuable pool of potential volunteers. These retirees will have a lot to offer, but Berry believes they will also have high expectations of the charities they support.
"This generation will contain a lot of stroppy older women who want a bit more," she says. "They will have a different view from their grandparents, who were happy to make tea and cake. They will want more fulfilling roles, and roles involving leadership. They will have many calls on their time. They will volunteer with enormous commitment, but as and when they can."
Older people are traditionally the sector's strongest supporters, but Berry warns there might be more financial pressure on the next generation of senior citizens. "There's a lot of work being done on using social media to get young people to give," she says. "But there's not much that's new, exciting and different for older people. No one has really asked older people what they want."
She says charities must also understand the effect the ageing population will have on service delivery. "An NPC report on the charity Relate, for example, shows that they are getting more people coming in who are over 65," she says. "They have had to rethink their services entirely to focus more on relationship issues in old age.
"All kinds of charities, whatever their cause areas, will have to change the way they operate."
