Perth accountant Peter Stamatopoulos was handed down the eight-year sentence, with a non-parole period of four years, after he pleaded guilty to lodging fake tax returns on behalf of both family members and clients without their knowledge.
In a statement, the ATO said Mr Stamatopoulos abused his power as the director of an accounting firm to amend company, trust and individual tax returns in order to claim false imputation credits.
The accounting firm he worked at discovered the fraud had taken place over a period of four years between 2011 and 2015, and immediately reported the discovery to authorities.
According to the ATO, the firm fully cooperated in the investigation and returned a total of $211,000 to the ATO.
Sentencing judge Michael Bowden of the Perth District Court described the matter as a serious offence involving a considerable sum of money and emphasised that the deceit had taken place over an extended period of time.
As part of the verdict, the Commonwealth was also awarded reparation of $884,664.97. A further $815,000 was recovered through search warrants executed by the ATO and the Australian Federal Police.
“When anyone claims more than they should, they are depriving the Australian community of vital funding. Fraud of this magnitude is very damaging to the Commonwealth and honest taxpayers,” said ATO Deputy Commissioner Will Day.