A Government agency set up to protect children has branded hundreds of innocent people criminals, it emerged.

The Daily Telegraph newspaper reported that in the year to February almost 700 applicants for jobs in teaching, nursing, childminding and volunteer work had been falsely accused of wrongdoing by the Criminal Records Bureau (CRB).

The news comes as ministers prepare to increase the number of criminal record checks carried out on the public.

The CRB was established to vet people working with children. In recent years the number of checks undertaken annually has almost doubled, from 1.5 million five years ago to almost 3 million last year.

But the Daily Telegraph said it had learnt that the agency is plagued by delays and mistakes.

The newspaper claims that some 680 people were issued with incorrect information in the 12 months to February 2008.

Applications from more than 50,000 people requiring "enhanced checks" because they work unsupervised with children had to wait more than two months to be processed.

It also emerged that the CRB's 450-strong staff claimed more than 5,000 sick days last year, working out at about two weeks per person.

Speaking to the Daily Telegraph, David Ruffley, a shadow Home Office minister, said the mistakes were evidence of an "emerging crisis" of public confidence in the handling of public information.

He added: "Jacqui Smith (the Home Secretary) is responsible for this continuing incompetence, mismanagement and delay. Despite obvious public concern she seems incapable of getting a grip."