The Morrison government will push ahead with a crackdown on unions through new measures making it easier to deregister unions and disqualify officials.

Legislation is expected to be introduced to the House of Representatives on Thursday, with Industrial Relations Minister Christian Porter set to return the Ensuring Integrity Bill to parliament.

Union officials would be subject to a “fit and proper person test”, while the minister or anyone with a “significant interest” could apply to de-register a union.

A public interest test would be imposed on mergers, like the amalgamation of powerful left-wing construction and maritime unions.

Prime Minister Scott Morrison put industrial relations on the agenda after his shock election victory, vowing to revive the bill the government says aims to stamp out union lawlessness.

Crossbench senators killed the legislation in the last term of parliament but the coalition is dealing with a smaller group of independents and minor parties in the new make-up.

The government will need four of six crossbenchers to get the bill through when it reaches the upper house.

Former Liberal Cory Bernardi and One Nation’s two senators are expected to back the changes, but Centre Alliance’s two votes will likely depend on extending the measures to corporations.

Tasmanian senator Jacqui Lambie could hold the crucial vote if the government insists on passing the bill without amendments.

Australian Council of Trade Unions president Michele O’Neil described the legislation as dangerous and extreme, saying it was important people were free from government and employer interference.

“All Australian workers benefit from the work of unions. If unions are shut down or silenced, who will stand up to the powerful, make sure workers get their rights and fight to improve workers’ rights?” she told AAP.

“The Morrison government has overseen raids on journalists and is now attacking working people’s freedom to run their own unions. These are dangerous attacks on fundamental pillars of democracy.”

The coalition is aiming to capitalise on controversy surrounding Victorian construction union secretary John Setka, with the ACTU calling for him to quit and Labor trying to expel him from the party.

The firebrand union boss was convicted of domestic violence offences including harassing his wife and breaching a court order, but is refusing to budge.

Governor-General David Hurley confirmed the bill would form an important part of the coalition’s industrial relations platform when he outlined the government’s agenda on Tuesday.