The CFMEU is reeling after it was forcibly placed into administration, but a potential court challenge could undermine the government's attempt to rein in the disgraced union.
Laws giving the relevant minister powers to intervene and slap life bans on CFMEU officials passed the parliament this week.
Attorney-General Mark Dreyfus on Friday placed the union's construction and general division into administration, alongside all of its state and territory branches, declaring it was in the public interest.
More than 200 elected CFMEU officials were immediately terminated and any union property they possessed, such as cars, mobile phones, laptops and documents, could be taken.
Executive members including national secretary Zach Smith have retained their positions, but they are now subject to the powers and directions of the administrator.
The CFMEU's NSW and Victorian branches said the government's moves "have done nothing more than attack the rights and conditions of thousands of CFMEU members and their families".
"This entire farce was born through a baseless media and government stitch-up," branch leaders said in identical statements.
"The lack of due process and basic democratic rights from this government is disgusting and simply un-Australian."
Awards and enterprise agreements that cover CFMEU members will remain in place, RMIT Graduate School of Business and Law professor Anthony Forsyth said, but the union is no longer run by elected officials.
"Effectively, the administrator is now running the union," Prof Forsyth told AAP.
In the days since the laws passed, the CFMEU has signalled it will launch a court challenge.
Prof Forsyth says the union has a variety of legal avenues.
They could argue Mr Dreyfus had acted beyond his powers as his decision to launch the administration process took irrelevant considerations into account, such as unproven allegations against CFMEU officials.
This would mean it is "infected with improper purposes and is therefore unlawful", Prof Forsyth said.
Union lawyers could also claim the laws excluded rights of natural justice and procedural fairness before taking drastic action.
Otherwise, a legal challenge could be launched against the administrator, seeking a judicial review of his actions on the basis he is acting unlawfully, Prof Forsyth said.
The government's move follows allegations of corruption and bikie infiltration within the CFMEU.
Prime Minister Anthony Albanese said it was part of an effort to clean up the industry.
"We know that trade unionists do a great job when they're looking after the wages and conditions of their members, but there's no place for corruption or intimidation in the building industry from unions," he told reporters in Townsville.
Melbourne silk, Mark Irving KC, has been given the job of administering the CFMEU, which involves taking over management functions, investigating allegations of criminality and corruptions, and co-operating with law enforcement authorities at state and federal levels.
He will also work with Fair Work Commission general manager Murray Furlong to ensure the disgraced construction and general divisions can effectively operate.
The administration period can last up to five years and officials found guilty of crimes would be banned for life and unable to become bargaining agents at other registered organisations without holding a fit-and-proper-person certificate.
Master Builders Australia and the Business Council of Australia both welcomed the move.
Victorian Opposition Leader John Pesutto supported the administration process but suggested the federal government should have gone further.
"The culture is so rotten inside the CFMEU and so toxic that there's no hope of ultimate recovery from this," he said.
The Victorian government's independent review into the alleged criminal misconduct is due to deliver an interim report by Thursday.
Victoria Police Chief Commissioner Shane Patton said the force would decide in coming weeks whether to investigate individual CFMEU members.
