The Government's latest package of measures to improve the Criminal Records Bureau (CRB) could make matters worse for small charities.
Home Secretary David Blunkett announced measures to improve the running of the bureau on 27 February following an independent review of the CRB's operations.
But NCVO is concerned that the planned changes still fail to address the specific problems faced by the sector when conducting checks on staff and volunteers.
NCVO spokesman James Georgalakis said: "The Government is putting barriers in the way of volunteering, but this is something that it is supposed to support."
The CRB was set up to check the criminal records of those working with children and vulnerable adults, but has been blighted by inefficiency since it became operational in March 2002.
In order to make checks, organisations must either pay a £300 registration fee or find another registered body to request the checks on their behalf. Small charities have had difficulty finding registered bodies, since there is no systematic way of searching for them. Those that are successful often have to pay up to £15 per check in administration charges despite being exempt from CRB fees.
Blunkett's proposed changes include revising the role of registered bodies, re-establishing the CRB as an independent Home Office agency and introducing electronic applications.
NCVO is particularly concerned about the proposal to revoke the registered status of bodies which do not meet a minimum number of checks a year.
It argues that this will make it even more difficult for smaller charities to access CRB checks on staff or volunteers.
NCVO also attacked the plan to re-establish the CRB as an independent Home Office agency.
"If a new body is set up, there is a danger that all the experience that we have built up will be lost and we will be back to square one," said Georgalakis. "It is not a solution to just scrap the whole thing and start again."
The Home Office is planning a consultation with CRB users before the measures are put into operation. This would give NCVO an opportunity to reassert its concerns.
NCVO recommends several key reforms to improve the CRB. These include the funding and establishment of a back-up network of registered bodies and encouraging local authorities to act as registered bodies.
It also recommend improved training for helpline staff, since some charities have received conflicting advice.