The passage of laws making it easier to deregister unions and ban officials has been delayed, with the government yet to drum up crossbench support.

The Morrison government's "ensuring integrity" bill will not be voted on in parliament this week, leaving the government the final sitting fortnight to get the regime in place before the end of the year.

Pauline Hanson and independent Jacqui Lambie hold the key, with support from either senator enough to clinch victory for the government.

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But the One Nation leader, who controls two votes, and Senator Lambie are yet to come on board.

Attorney-General Christian Porter, who is also industrial relations minister, said the government had negotiated with crossbench senators during the week.

"I am confident we are close to securing a bill that will achieve the primary object, to establish a legislative regime that requires all registered organisations - unions and employer associations - to operate within the law," he said on Thursday.

Labor is urging crossbenchers to vote against the bill outright, even if it's amended.

"We want them to oppose the bill because effectively this is a bill that punishes workers," opposition industrial relations spokesman Tony Burke told the ABC.

READ MORE Coalition forges ahead in union crackdown

He said the government was weakening unions tackling wage theft at a time when it was a major issue for Australian workers.

"That point hasn't been lost on the crossbench," Mr Burke said.

Unions fear they will face deregistration for accumulating paperwork offences, like inaccuracies in financial or membership records.

But Mr Porter flatly rejected the concern.

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"Claims that by establishing effective deterrents for law-breaking the bill will give rise to the law being weaponised or unions being deregistered for minor paperwork offences are absolute nonsense," he said.

He said the bill simply required unions and employer associations to operate within the law.

"Where they don't, the bill provides a mechanism for the independent court system to determine whether action should be taken against individual officials or the registered organisation."

READ MORE Government pushes union crackdown forward

Mr Porter also took aim at the construction union's "law-breaking" business model he says is adding millions to building roads, schools and health services.

Australian Council of Trade Unions secretary Sally McManus and president Michele O'Neil also spent the week lobbying crossbench senators.