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.
"As the matter is now before the court, police are unable to comment further," McPherson said.
Krishnan appeared before Community Magistrate Lauolefale Lemalu and was remanded without a plea.
Te Whatu Ora Health New Zealand said the person was employed in February and held a clinical research position.
The agency said it supported the hospital in referring the matter to police.
Health Minister Andrew Little also told RNZ he was advised of the allegations on August 10 and was satisfied with Te Whatu Ora's response.
Krishnan will next appear in court on September 7.
