“MyTax is not an approved lodgement channel for registered agents and is a breach of the ATO online terms and conditions,” the ATO said.

“We will be closely monitoring returns and utilising all of our data-matching and collection tools in an effort to identify suspicious patterns of behaviour with lodgements. We will seek to identify patterns of behaviour that suggest the use of myGov by unregistered preparers.”

The ATO said that online services for agents should be used for managing a client’s tax affairs.

“Agents may risk referral to the Tax Practitioners Board if they are discovered using myGov to lodge on behalf of their clients, or without their clients’ knowledge,” it said.

“If you are concerned about the conduct of a tax professional, you should submit a complaint with the Tax Practitioners Board.”