Estimated figures compiled by the Charities Aid Foundation show that revenue generated by payroll giving has decreased since last year.
The figures from the Charity Trends 2005 report show that although payroll giving was worth £91m last year, this year it is expected to drop to £82m.
Report author Cathy Pharoah played down the decline. She said: "The simple reason for the drop is that the government scheme to supplement every donation by an extra 10 per cent has ended. There hasn't been a huge growth in take-up, but then again it hasn't declined. It's stayed pretty level."
Zarine Kharas, chief executive of www.just giving.com, is less optimistic.
She said: "We ended up dropping payroll giving last year because the market was so tiny."