Carrying out Criminal Records Bureau checks has cost the voluntary sector £220m over the past eight years, according to a new study.
The report was carried out by the Manifesto Club, which has been campaigning against the Safeguarding Vulnerable Groups Act since 2006.
It says that since 2002 there have been more than four million CRB checks on volunteers, mainly those who come into contact with children.
The number went up from 239,731 in 2002/3, to 756,905 in 2008/9.
The report says the vetting and barring scheme, under which staff and volunteers working with children and vulnerable adults would have to register to be checked by the Independent Safeguarding Authority and which was put on hold by the government earlier this month, would have cost the voluntary sector an additional £136m.
The report says the bureaucracy to which volunteers are subjected is "completely out of proportion to the informal and low-key nature of their activities" and cites examples of people being asked to complete CRB checks for activities such as flower arranging in a cathedral and listening to children read in a school.
It says some volunteers are resigning in protest, and other potential volunteers are deciding not to take up opportunities because they feel as if they are being treated with suspicion and subjected to "invasive procedures".