The former head of the Health Services Union (HSU) Michael Williamson has had his bail revoked after his sentencing heard his "downfall has been complete".

Last year, Williamson pleaded guilty to funnelling almost $1 million from the HSU to businesses he had an interest in.

The charges include recruiting others to hinder a police investigation and two counts of defrauding the HSU.

During Williamson's sentence hearing, prosecutor Emily Winborne told the court he had created an environment within the HSU where his behaviour would not be questioned.

By creating a series of false invoices made out to the company CANME, which was in his wife's name, the then union boss began systematically defrauding the union of $340,000 from 2006 to 2009.

He also defrauded printing firm Access Focus of $600,000 between December 2006 and February 2010.

Once inquiries into the union's financial mismanagement began, Ms Winborne said the length to which Williamson went to cover up his criminal activity was extraordinary.

She submitted that Williamson was motivated "purely and simply by greed" when he carried out the offences, noting his salary during that time ranged between $290,000 to more than $500,000.

But forensic psychiatrist Dr Bruce Westmore said Williamson's early life had left him anxious about providing for his children.

"He wanted to do better for his children than his parents were able to do for him," he told the court.

Williamson's barrister, Timothy Game SC, said the former national ALP president had issued an apology to the HSU and taken full responsibility for his actions.

"His downfall has been complete," Mr Game told the court.

"His public reputation, his financial and personal circumstances, his future - everything has been brought down."

In a reference, one of Williamson's children says despite his serious wrongdoings she is proud of him.

Williamson was caught trying to shred documents when he was confronted by the NSW Fraud Squad at the union offices in Sydney's CBD.

He is due to be sentenced later this month.

ABC/AAP