"The only other factor is that sometimes locums come by word of mouth. They might have worked in other practices in the area for a year or two. That was the case with Marcus. He wasn't an unknown face."
Dr Hawkins said that even at his own clinic he had not checked the passports of locums he had hired.
He had urged the council - which controls registration and issues practising certificates - to add photos alongside the publicly available registration information on each doctor on the council website, but it had declined.
He said that without such photo ID, and without routine passport checks by all medical employers, it would be easy for an overseas doctor who was not registered in New Zealand to trick a clinic into thinking they were permitted to practise here.
All they would have to do is learn the name and details of a fully licensed GP in one region and dishonestly name themselves as that person to an employing clinic in a distant region.
If they built a good reputation they would have no difficulty moving from clinic to clinic undetected.
Dr Hawkins said it might have happened already.
"If there's a person masquerading as a second- or third-year medical student I wouldn't be surprised if somebody is doing it as a doctor."
The council said it was the responsibility of doctors themselves - and their employers - to ensure they were fully licensed.
