The former national president of the CFMEU says a legal challenge has been launched in the High Court to laws forcing the construction union to accept administration.
The federal government passed laws with the support of the Coalition to force the union to accept an administrator after it became evident a legal administration process would take weeks or months.
The union faces allegations of consorting with organised crime groups, corruption and "thuggery".
On Tuesday the sacked CFMEU heads filed a challenge, claiming a forced scheme of administration was unconstitutional and undemocratic because it violated union members' rights to due process.
The union's former national president Jade Ingham said that legislation had "stolen" the CFMEU from its members.
"The most important people in this are the members of the CFMEU whose voices have been excluded. Members are furious about their union being taken away from them," Mr Ingham said.
"This is active treachery and class warfare against the working class in this country from the state and federal governments."
Mr Ingham said the group's goal was to have the laws declared unconstitutional and the administrator removed, "in the same way that 2,750 democratically elected office-holders from our union were removed" last month.
A team of barristers headed by Bret Walker SC will run the challenge, which was lodged by the CFMEU's former Queensland secretary Michael Ravbar and the state assistant secretary.
Prime Minister Anthony Albanese said the legal challenge was entirely expected.
"Surprise, surprise. [Former Victorian secretary] John Setka took our entire national executive to court over him being expelled from the Labor Party," he said.
"That's fully expected. We will stand by our position and the government's position will be defended."
When Workplace Relations Minister Murray Watt announced the legislation to force an administrator, he said the laws had been designed to best withstand a legal challenge by the CFMEU's former bosses.
Shadow Workplace Relations Minister Michaelia Cash said those laws were the start of "cleaning up" the union, and the federal government should now back the Coalition's push to re-establish the Australian Building and Construction Commission, which the government abolished after its election win.
The former president said a crowdfunding effort had been launched to support the legal challenge.
Mr Ingham said the Electrical Trades Union and United Firefighters Union were publicly supporting the crowdfunding effort, as well as other unions privately.
"These laws should concern any Australian who is concerned about our democracy and who cares about our country," Mr Ingham said.
"These laws have been put in place by a bunch of politicians who have now usurped the entire legal justice system … in response to a TV show."
CFMEU national secretary Zach Smith has been contacted for comment.