Originally set for a July launch, the CRB's official unveiling was postponed until the autumn after fears were raised over the reliability of data from the Police National Computer (PNC).
Earlier this year a Home Affairs Select Committee report revealed that as much as two-thirds of the PNC data - used to check the police record of job applicants - was inaccurate.
A spokesman for the CRB said: "We are making good progress with sorting out the problems with the system, but we will probably have to launch with a limited operation.
"It is vital that the bureau is efficient when it is launched and our primary concern is to offer a robust service."
CRB's private sector partner, Capita, is responsible for developing its IT infrastructure, recruiting staff to operate its call centre and making initial identity checks on applicants.
A joint Capita and CRB statement said: "Working in partnership, the CRB and Capita are making good progress against the revised timetable and are committed to delivering a quality service to its customers. We recognise, however, that this is an ambitious project, and that there is a balance to strike between sticking rigidly to timetables and ensuring that the system and its processes are fit for the purpose."