Unions will fight Morrison government plans for new laws making it easier to deregister industrial bodies and ban officials.
Industrial Relations Minister Christian Porter is seeking to bring back to parliament a bill enabling the Federal Court to disqualify officials if they are not a "fit and proper person" and cancel the registration of unions on a range of grounds.
He also says the peak construction and mining union, the CFMMEU, should be deregistered.
The CFMMEU was on Friday fined $100,000 after two union officials acted improperly when attempting to enter two Melbourne worksites in 2014.
One of its most senior officials, the Victorian secretary John Setka, is facing a push by Labor to expel him from the party and from the union movement to have him stand aside as an official.
He's accused of telling colleagues anti-family violence campaigner Rosie Batty's advocacy has led to men having fewer rights but rejects the claim.
Australian Council of Trade Unions president Michele O'Neil said the government's proposed laws were an attack against basic democratic freedoms.
"Unions are democratic organisations and attacking them hurts all working people," she said.
"This law will undermine workplace safety, increase wage and superannuation theft and make it harder for workers to get pay increases and be represented when they need help."
The building industry says the Ensuring Integrity Bill is about making unions more accountable and bringing them into line with community expectations.
Officials who do not live up to their obligations should face "real and meaningful consequences", Masters Builders Australia chief Denita Wawn says.
The government believes "unlawful organisations" should not enjoy the rights and benefits of lawful registration.
The bill was introduced to parliament in 2017 but suffered a blow last year when the coalition couldn't rally enough support among the Senate crossbench.
In the new parliament, the coalition will need the support of at least four crossbench senators to pass the bill.
