An unregistered doctor who worked for six days in the emergency department of a South Australian hospital repeatedly lied about his status, investigations have found.
The overseas-trained doctor worked at the Port Augusta Hospital, in the state's mid-north, between April 24 and May 2 before being removed from the premises.
The Australian Health Practitioner Regulation Authority and Australian Medical Board later offered him provisional registration with conditions.
But the bungle was referred to SA Police, the Australian Health Practitioner Regulation Authority and other investigative bodies for further action.
SA Health on Wednesday said two independent inquiries had found the doctor had intentionally and repeatedly lied to staff about the progress and status of his registration application.
It said the doctor deliberately misrepresented himself to staff and patients at the hospital to gain unauthorised access to the emergency department.
Department for Health and Wellbeing chief executive Robyn Lawrence said the recommendations from the investigations were being worked through to make sure hiring processes were "as thorough and robust as the public expects them to be".
"Our workforce team will be coordinating these measures to avoid an incident like this happening in the future," Dr Lawrence said.
The findings of one investigation found a critical shortage of junior clinicians had prompted officials to accept an application from a "far-from-ideal applicant".
It said flaws in recruitment and selection methods allowed the doctor to proceed through the process without serious scrutiny.
"These flaws included a lack of critical analysis of (the doctor's) CV, poor interview planning and technique, failure to critically analyse referees and their reports and a failure to perform timely basic background checks," the investigation found.
The doctor treated at least 15 patients with each contacted to discuss their care needs and to determine if a follow-up appointment was required.
SA Health has said it was not aware of any adverse clinical outcomes.