Charitable giving has dropped by 25 per cent as a proportion of GDP over the past ten years, Stephen Ainger told the CAF conference last week.
Despite an upturn in donations since 2000, brought on by government tax incentives and more professional fundraising techniques, giving is still not increasing in line with the growth of the economy, the CAF chief executive said.
"This is a major issue for charities, which can only be addressed by changing the culture of giving, which includes the need for charities to be much more transparent about what they do and the impact they have," he told delegates.
Ainger also branded the fact that only 33 per cent of donations are given tax-effectively "a disgrace", and said charities must smarten up their act.
He called on them to increase the number of employees participating in payroll giving by 250,000 over the next five years. And he urged Chancellor Gordon Brown to extend the 10 per cent supplement on payroll giving for another three years.