The Coalition’s centrepiece industrial relations bill will be introduced in Parliament today, and has already kicked off a furore.

Labor and the Greens have opened fire on the attempt to bring back what they see as the worst part of the WorkChoices era, while the Prime Minister has hinted that their refusal to get on board may trigger an early election.

The Government is trying to reinstate the construction industry watchdog, the Australian Building and Construction Commission (ABCC).

The LNP has got itself stuck by trying to argue that the recent findings of the royal commission into trade unions showed why the ABCC should return, but that it will not show the Opposition that evidence.

Workplace Relations Minister Michaelia Cash says Labor and the Greens could join crossbench senators in viewing a redacted version of the documents, with the names of witnesses removed.

The attack on unions in the wake of the royal commission is a strategy for the LNP this year, according to recently leaked talking points

Greens industrial relations spokesperson Adam Bandt said; “Everyone who is being asked to vote on this legislation — which we're being told is necessary because of the material in this secret report — should be entitled to see the report.”

“There should be one class of senators and not two,” Bandt added.

The bid to reinstate the ABCC failed in the Senate last year, and there does not appear to be much more support for it this time round.

South Australian Family First senator Bob Day and Liberal Democratic senator David Leyonhjelm say they will vote for the law, while Senators Nick Xenophon, John Madigan, Dio Wang, Jacqui Lambie, Ricky Muir and Glenn Lazarus have told reporters they are undecided or undeclared.

Somewhat unsurprisingly, one of the original backers of the ABCC says it should come back.

Terence Cole chaired the royal ­commission under the Howard government that paved the way for the Australian Building and Construction Commission.

In a letter sent to and published by News Corp this week, he argued that anyone opposed to its return risked entrenching unlawful union conduct and costing the economy billions.

“Surely it is incumbent upon those who oppose the reintroduction of the ABCC to explain how it is to the advantage of the Australian economy, and to the Australian people who bear the great costs of unlawful action, to have an increased level of unlawfulness in the building and construction industry which the ABCC has demonstrated it can suppress, but which existing arrangements do not,” Mr Cole said.

Mr Cole said that by 2007, the original ABCC brought savings of $3.1 billion a year by reducing unlawful union conduct.

He backed figures from industry lobby Master Builders Australia that claim the re-introduction of the ABCC would be worth $6.3 billion a year by 2012.

“There may be debate regarding the precision of the assessed savings, but on any view, consequential benefits to the economy due to the effectiveness of the ABCC in diminishing unlawful and inappropriate conduct were very great indeed,” he said.

“The Heydon royal commission report established that unlawful and inappropriate conduct was again prevalent in the building and construction industry. No doubt such conduct carries with it the deleterious costs to Australians, as it always has.”

In a slightly startling turn on Tuesday, Prime Minister Malcolm Turnbull told Coalition MPs that failure to re-establish the ABCC could be a double dissolution trigger, forcing an election of all sitting members across both houses of parliament.

The comments have been interpreted by some crossbenchers as a threat to their positions, and a strong-arm tactic to make them vote the Government’s way.