Some applicants for jobs with the Whanganui District Health Board have misrepresented their qualifications and credentials.
However, the health board is confident it has procedures in place to catch any further attempts at fraud.
General manager human resources Hentie Cilliers said some applicants for positions in Wanganui had "misrepresented or exaggerated some aspects".
"This has been picked up prior to, or at, the interview stage and has resulted in non-appointment."
Mr Cilliers comments follow allegations that a man stole an American doctor's credentials and worked in Waikato as a psychiatrist for seven months.
Mohamed Shakeel Siddiqui, 54, is before the Hamilton District Court charged with obtaining by deception after being accused of using the credentials of a US doctor to get a job at the Waikato District Health Board.
Andrew Connolly, chairman of the New Zealand Medical Council - the body in charge of checking whether overseas doctors are fit for practice in New Zealand - said the allegations appeared to point to a "very sophisticated" identity theft which, if proven, would go down in history as an "exceptional" case.
Medical professionals at Whanganui Hospital who are hired from overseas are supervised for 12 months.
Mr Cilliers said the health board had an "extensive" recruitment process for new senior medical officers, which included independent checks, a Google name check, and health screening.
Applicants had to have three written references from recent senior medical colleagues, have an interview with a panel, and have a face-to-face interview with the Medical Council of New Zealand.
"Doctors must provide their passport, visa, driver's licence, certificate of good standing and original qualifications prior to being issued with a practising certificate," Mr Cilliers said.
"Whanganui DHB also sights the doctor's passport, visa, and driver's licence. Copies of these and their qualifications are kept on their personnel file ... All offers made are subject to police checks, reference checks, NZ Immigration and NZ Medical Council."
He said a "comprehensive" orientation was provided for all new employees, and doctors appointed from overseas were under supervision for 12 months.
The Medical Council says more than 6000 international medical graduates hold practising certificates in New Zealand - 42.5 per cent of New Zealand's health workforce as of August 6.
Mr Connolly said the vast majority made very positive contributions in New Zealand.
"Ideally, we would have more New Zealand doctors, but it's not that simple. We need overseas doctors to fill important roles, particularly in shortage areas and small rural parts of New Zealand that it can often be hard to get people for.
"This isn't just unique to New Zealand - most countries rely on a mix of native and international medical professionals."
He said most overseas doctors were very committed to their work. "And a lot have families that they bring with them, so they're not only trying to build their lives professionally, they're also making new lives for their partners and children."