Some cash-strapped groups estimated new costs of $5000 to $10,000 a year if they needed to pay for criminal checks.
Cancer Society chief executive Claire Austin said her organisation, which had "extremely limited funds", needed to vet about 1500 people a year for volunteer jobs such as supporting people in the final stages of cancer and driving them to treatment.
In a sector where "every cent counts", the society would face a bill of about $10,500 unless exempted by the Government.
The Blind Foundation said it looked after a large number of children, and under a law change last year it was required to vet all its staff. It estimated a new bill of at least $2500 a year.
The Police Association agreed with the groups. Its members supported moves to reduce the strain on the frozen police budget but believed cost recovery should be limited to private commercial interests.
The bill would give powers to the minister to make exemptions but it's not yet clear how these will be used.
Police Minister Michael Woodhouse could not be reached yesterday, but his predecessor, Anne Tolley, emphasised that the proposed charge was much lower than the $50 to $60 paid for criminal checks in parts of Australia.
The Teachers Council, which is legally required to vet teachers and makes 40,000 checks a year, also opposed the bill.
Acting director Rob McIntosh said vetting was one of the police's core functions and it should not be considered an additional service such as dealing with lost and found property or running the Police Museum.
He said police vetting of teachers was one of the key tools for protecting children and young people.
Criminal checks
• Between 450,000 and 500,000 criminal checks a year
• Estimated cost to police of $2.2 million
• Some organisations, such as those that work with children, legally required to vet staff
• Government wants to charge $5 to $7 for checks.