Liberal Democrat MP Paul Burstow made the accusations in a highly critical debate into the computer fiasco at the CRB at Westminster Hall, the second chamber of the House of Commons.
The bureau was set up to allow checks on the records of those applying to work with children and other vulnerable people to weed out paedophiles and other undesirables, but has suffered major problems.
Burstow said the IT system supplied by Capita for the CRB "basically lacks capacity'' which caused massive delays and a backlog of application forcing the Home Office to order the use of paper-based systems instead.
He called for publication of a confidential report by consultants The French Thornton Partnership into the problems. The report, commissioned five months after the Capita IT system went live and seven months behind schedule, revealed "a catalogue of serious defects" said Burstow.
"Software and applications were poorly documented, poorly coded and not adaptable enough to meet future business needs without major modifications.
"There is even a question mark over whether the system originally delivered by Capita was capable of coping with the demands of basic disclosure.''
If this was true, said the MP, it was no surprise that a later inquiry by troubleshooter Sir Patrick Carter found that despite "substantial enhancements and improvements" it lacked the capacity to handle the levels of demand forecast and was "still in need of significant modification to make it fit for its intended purpose''.
Burstow demanded to know if the system was fit for its intended purpose when delivered, and if not why not who was to blame.
Home Office minister Hilary Benn did not answer directly but said, "I will undertake to investigate whether there is any possibility of the French Thornton Report being released in part or in whole.''
He apologised for the problems, which meant some teachers had to start work without being vetted, and said a National Audit Office inquiry would outline what had gone wrong when it was published.
Benn said measures to improve performance were now working and the new mandatory checking of criminal records regime was soon to be phased in. The question of fees and cost recovery was now being considered.
He admitted that there had been repeated problems with the procurement of public sector IT systems but added "that it is not unique to the current government.".