The call, from the NHS Counter Fraud and Security Management Service, follows the conviction of a human resources manager for fraud.
Attah Okoji, who pleaded guilty to lying to gain work as an assistant HR manager at Northumberland, Tyne and Wear Mental Health trust through a local employment agency, is awaiting sentence.
He worked at the trust over three periods from November 2007 despite having a criminal record. In 2001 he had used a former job to divert£16,000 into his own bank account, for which he was jailed for six months. In 2004 he gained a job at a Leeds health body by failing to declare his previous conviction and submitting false credentials, and was sentenced to community service.
Counter Fraud Service head of operations Allan Carter said trusts needed to carry out random checks on work agencies. He said: “We also expect them to report agencies that fail to fulfil their obligations in pre-employment or reference checking so we can investigate further.”