Former Health Services Union boss Michael Williamson has been sentenced to seven-and-a-half years in jail for fraud.

The New South Wales District Court was packed as sentencing Judge David Frearson described Williamson as "brazen and arrogant".

The judge said Williamson was in a position of power when he defrauded the union of nearly $1 million.

The former Australian Labor Party president submitted false invoices to the union from a company in his wife's name.

Judge Frearson described Williamson's "parasitic plundering of union funds for pure greed".

Williamson showed no emotion as he discovered his fate and sat staring at the judge until he was led away.

The 60-year-old will be eligible for parole after serving five years in prison.

Judge Frearson said Williamson "exercised extreme power" and had an income of around $500,000 at the time of the offences.

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The court heard the fraud was planned over several years and the "leached union funds" were used to fund Williamson's lifestyle.

Williamson's lawyers had argued he had apologised and taken full responsibility for his actions, noting he has also suffered depression since his behaviour was exposed.

But Judge Frearson said there was no psychiatric excuse for the offences, which he described as a "reprehensible betrayal of the union".

"He is remorseful at this point," Judge Frearson said, noting that he believed Williamson is unlikely to reoffend.

Williamson had been facing a possible 20 years in jail after pleading guilty to four charges including fraud and recruiting others to hinder a police investigation.

Among those in the court for the sentencing was HSU national secretary Kathy Jackson.

Outside court Ms Jackson said the jail term was a victory for the HSU.

But Ms Jackson said she still has concerns about the union and is very much in favour of a royal commission.

A longtime HSU member, Doris Borg, was less satisfied with the sentence and had a simple message for Williamson.

"You're a thief, that's it. You've just taken advantage of low paid income workers and there's no need for it," she said.

"We've all gotta work for our money. What was he on? $300,000 and he still wanted more and he still wants more from it."

The jail term for Williamson comes in the same week former federal Labor MP Craig Thomson was sentenced in a Victorian court for defrauding the HSU.

Thomson was sentenced to 12 months' jail, with nine months suspended, for defrauding the HSU of more than $24,000.

He used union funds to pay for sex services and cigarettes.

Thomson is free on bail after lodging an appeal against the sentence.