Over that time, she attended to patients' dressings, took blood samples, injected patients with vaccines and immunisations and performed electrocardiograms.
However, her facade came undone when she was asked to provide evidence of her registration and she offered a sticky note with a false number.
The registration number did not exist on the nurses register and Elwell quit in December 2020 after the medical centre asked for a copy of her Nursing and Midwifery Board of Australia registration certificate.
Even so, she continued to insist she was registered.
Elwell was charged with 16 counts of holding herself out as being registered in breach of national law.
She failed to appear before the Windsor Local Court on March 24 and was convicted in her absence, with the magistrate issuing a warrant for her arrest.
Elwell was then arrested on April 5 and returned to court for sentencing on Thursday, where she was fined AU$3000 (NZ$3298) and ordered to pay AU$7200 (NZ$7916) in legal costs incurred by the prosecuting agency, the Australian Health Practitioner Regulation Agency.
Magistrate Leanne Robinson said Elwell's actions involved "deliberate deceit" and posed a "real risk to patients".
Elwell's difficult personal circumstances were taken into account in the sentence.
AHPRA CEO Martin Fletcher said he hoped the outcome sent a strong message that falsely claiming to be a registered health practitioner had significant consequences.
"We are committed to ensuring that such behaviour is dealt with and will act to protect the public," he said.
Nursing and Midwifery Board of Australia chair Veronica Casey said the act betrayed public trust in the profession.
"This type of conduct is completely unacceptable," she said.
