Disgraced former tax agent Richard Hogg.

A Maserati-driving tax agent from Beaumaris has pleaded guilty to dozens of fraud and dishonesty offences after stealing more than $1.3 million from 15 clients and almost $2.8 million from the Australian Tax Office.

Richard Hogg, 56, left a trail of financial destruction with his "efficient tax planning arrangements", but his victims face further hardship with the ATO continuing to pursue them for unpaid taxes.

County Court judge Duncan Allen expressed concerns about the lack of compensation for Hogg's victims, who included the best man at his wedding and former students from his alma mater Mentone Grammar.

"They thought they were paying tax. They, in fact, owe tax. It's a double-whammy for them ... the tax office is not known for the quality of mercy," Judge Allen said at the plea hearing on April 26.