A former Australian Labor MP, now an independent, has been arrested.
Craig Thomson will face 150 fraud charges relating to his time as head of the Health Services Union when he appears before a court in Melbourne next week.
Mr Thomson, who maintains his innocence, was released on bail on Thursday afternoon.
HSU national president Chris Brown said the union will try to recover money from Mr Thomson if he is found guilty of fraud, but warned the court processes will take a while to run.
The ABC reports HSU former national president Michael Williamson was last year charged with 48 offences relating to allegations he misused more than $A500,000 during his time at the union.
Mr Thomson's membership of the Australian Labor Party was suspended last April following a request from Prime Minister Julia Gillard, who said on Thursday that she only knew about the arrest through the media.
However, shadow attorney-general George Brandis said on Thursday night that the prime minister must rule out any link between Craig Thomson's arrest and her early calling of the federal election.
Senator Brandis told Lateline that Ms Gillard must explain whether the reason she called the election so far ahead of time was because she knew of Mr Thomson's impending arrest.
"Now, I'm not saying that there was a cause-and-effect relationship between those two things, but it is curious,' he said.
"The prime minister needs to make it clear that there was no such cause-and-effect relationship."
Ms Gillard announced on Wednesday the federal election would take place on 14 September.