Former Health Services Union boss Kathy Jackson is set to learn her fate for rorting more than $100,000 in member funds.
She spent the money on various overseas holidays, expensive artwork and a Mercedes-Benz.
Once lauded as a whistleblower against corruption herself, Jackson used work credit cards and dodgy expense claims to cover up her systematic misuse of HSU funds from 2003 until 2011.
The 52-year-old last month pleaded guilty to two charges of obtaining financial advantage to the tune of $67,792.85 by deception.
This allowed her previous jury conviction for one count each of deceptively obtaining property and financial advantage worth $35,100 to be reported.
That same jury acquitted Jackson of 18 theft and two deception charges.
She spent union funds on shopping trips to Hong Kong and India, and holidays to Bali, the US and Europe with family and friends.
In 2008, she used HSU money to buy a $22,000 Mercedes-Benz from the husband of a former union legal adviser.
That same year she arranged to be reimbursed for her purchase of a $4636 portrait by revered Australian artist Charles Blackman.
Jackson claimed it was for work but displayed it at her Balwyn home in Melbourne's east.
Other fraudulent purchases included a $1650 home entertainment unit, a $576 gift basket for a friend and ex-union lawyer, and more than $1000 of CDs, DVDs and console games.
She blew the whistle in 2011 on her predecessor, former federal Labor MP Craig Thomson, and former union general secretary Michael Williamson.
Victoria's County Court was last week told Jackson may not have to serve any jail time for her crimes, with a potential suspended sentence on the cards.
The 52-year-old remains on bail and is not expected to be in court in person when Thursday's sentence is handed down.