Obiyo Chigozie Nwigwe, 45, appeared via video link from prison at the Court of Appeal wearing a shirt and tie on Tuesday.

The Director of Public Prosecutions has lodged the appeal to argue Nwigwe should have received a higher sentence after his case was finalised in the County Court of Victoria last year.

Judge David Sexton sentenced Nwigwe in July 2021 to six years and six months' imprisonment, with a non-parole period of four years and three months. He said in his sentencing remarks Nwigwe's offending was a breach of trust and a breach of his oath as a doctor to care for others.

The former doctor at Bendigo hospital pleaded guilty to four charges of sexual penetration of a child under 16 and one of using a carriage service to transmit indecent images to a child under 16.

Nwigwe had met the child and her family after moving to Ballarat in 2019. The court heard on Tuesday the family felt they could trust Nwigwe as he was a "good Christian man" and an "honest and trustworthy doctor".

The crown prosecutor described him as a "wolf in sheep's clothing" as he "repaid their trust and generosity" by beginning to prey on the 13-year-old after his wife travelled overseas.

Nwigwe told the victim he loved her, kissed her and sexually penetrated her early on but the offending quickly escalated to "numerous acts" of sexual intercourse. In an exchange of almost 1000 messages, he also sent naked photos of himself to the victim.

Crown prosecutor Christopher Boyce QC said the 'bad offending' should have attracted a higher sentence than the one imposed.

"We have a case of a person who abused the trust and generosity of a family who has taken him in, offered him real support at a time of apparent vulnerability, and he has essentially used the complainant as a sexual play thing in his wife's absence.

"He extended her suffering by emotionally blackmailing her with the threat of his own suicide. The sentences in this case are manifestly inadequate."

The victim said Nwigwe had stolen her innocence and her childhood from her. She told the County Court in June she constantly felt physically sick, anxious, depressed and tired and had nightmares about the sexual assaults.

Nwigwe was married with three young children and living in Australia on a visa.

Defence barrister Colin Mandy S.C. said the County Court sentencing judge was "very experienced", particularly in cases of sexual assault.

He said his sentence was 'careful' and 'considered' and there was no specific error to complain of in his decision, the judge had used his discretion.

She told the County Court in June she constantly felt physically sick, anxious, depressed and tired and had nightmares about the sexual assaults.

Nwigwe was married with three young children and living in Australia on a visa.

Defence barrister Colin Mandy S.C said in his submissions during the appeal hearing the County Court sentencing judge was 'very experienced', particularly in cases of sexual assault.

He said his sentence was 'careful' and 'considered' and there was no specific error to complain of in his decision, the judge had used his discretion.

"He (the judge) found the sentence to be right in the middle of the available range," Mr Mandy said.

"This sentence is certainly not so far below the range that it represents an egregious error."

The court heard on Tuesday Nwigwe had been unable to see his children's faces while in custody because the prison did not allow video conferencing with children.

Mr Mandy said Nwigwe's permanent residency had been cancelled, which meant the court could assume he would serve 'every day of his head sentence'.

"Then there is the loss of his career as a qualified emergency specialist," he said.

"He has worked all his life to achieve that position, losing it all because of relatively short but alarming offending."

Nwigwe will return to court at a later date when a decision will be made on the Director of Public Prosecution's appeal.

Affected by this story? There is help available.

You can phone the Ballarat Centre Against Sexual Assault, in Sebastopol, on 5320 3933, or free-call the crisis care line 24 hours on 1800 806 292.

Or phone Lifeline on 13 11 14, the Blue Knot Foundation on 1300 657 380, or Relationships Australia on 1300 364 277.

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