Former doctor Jayant Patel's past patients are angry he has walked free from court and a former colleague is concerned he may seek work as a surgeon again.
The 63-year-old was handed a two-year suspended sentence on Thursday for fraudulently registering and working as a medical practitioner in Queensland.
Outside court in Brisbane the Indian-born US resident said he was pleased proceedings were over and would go "back to my life and my work".
The former Bundaberg Base Hospital nurse who blew the whistle on Patel said the reference to returning to work was alarming.
"I hope not," Toni Hoffman told AAP.
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"I still don't think he understands or accepts the gravity of what's happened."
Former patients said they were disappointed and angry Patel walked free from court, and upset he had shown no remorse for his actions.
"He has no remorse because he thinks he's done nothing wrong," former patient Beryl Crosby said.
"He got a two-year sentence; those who lost loved ones got a life sentence."
Ian Vowles, another patient who accused Patel of causing him grievous bodily harm in an operation, said the sentence didn't reflect the crime.
And the wife of one of Patel's patients who later died said she was "very disappointed".
"I'd love to have seen something done about it, but for the people that have passed on it's too late for them," said Vilma Blight, wife of Darcy Blight.
The Medical Board of Australia and the Australian Health Practitioner Regulation Agency announced they were taking legal action to prevent the disgraced former surgeon registering as a medical practitioner in the country again.
Patel is expected to return to the US where his wife and family live.
He showed little emotion as the sentence was handed down but told reporters outside court he was glad the "long and difficult journey" had ended.
"I'm pleased that it's over and I'll being going back to my life and my work," he said.
Judge Terry Martin told the sentencing hearing the seriousness of Patel's offending couldn't be overstated but took into account the two and a half years Patel had served in prison.
He said there was little doubt Patel's career was "forever ruined".
The court heard Patel lied about professional disciplinary action in the US to Queensland medical authorities so as to gain employment as head surgeon at Bundaberg Base Hospital in 2003.
He returned to the US under a cloud in 2005 before being extradited to Queensland in 2008 to face allegations of killing and maiming patients.
In 2010 Patel was convicted of three charges of manslaughter and one of grievous bodily harm and sentenced to seven years' prison, but the convictions were quashed on appeal.
Criminal negligence charges against him were finally dropped last week after two retrials failed to secure a conviction.
