As many as 200 unregistered or fraudulent nurses could currently be working in GP practices throughout the UK, it is claimed.
The arrest of a 46 year-old woman in Kent, who allegedly pretended to be a registered, qualified nurse by acquiring a nurse's Nursing and Midwifery Council (NMC) pin number illegally, has prompted the NMC to address GPs.
Worryingly, the unnamed woman worked for several years at a GP practice without being detected as a fraud.
A survey carried out by the NMC at the Royal College of GPs annual conference highlighted that 80% of GPs were not aware it was their responsibility to check the registration of the nurses they take on.
By not doing so, GP practices could face legal action and invalidate their medical insurance.
"Employers have a responsibility to ensure staff hold the necessary qualifications and registration," a spokesperson for the NMC said.
"GPs must ensure nurses are registered before they begin work and regularly check their registration status."
Dr Andrew Mimnagh, a GP in Waterloo, Merseyside, and Chair of Sefton Local Medical Committee, said: "I am amazed this many doctors are unaware of their responsibility as employing staff who are not qualified would invalidate any practice indemnity."
The NMC is currently preparing a letter to PCTs urging practices to check nurses' registrations properly.