The 30-year-old was employed as a clinical researcher at Auckland's Middlemore Hospital until questions were raised about his medical qualifications and he was sacked on August 10.
He reportedly examined dozens of patients during his time at the hospital.
Today Detective Senior Sergeant Veronica McPherson said police had charged a man with forgery.
"Police would continue to investigate the circumstances of the case. We are not ruling out additional charges being laid but this will depend on our ongoing inquiries.