Labor’s closing loopholes bill has passed the Senate with a Greens amendment creating a new right for employees to disconnect from work emails and calls.

But the final votes were thrown into confusion by the discovery that the bill inadvertently allowed criminal penalties for breach of a stop order by the Fair Work Commission. Labor sought leave to amend this, but was denied by the Coalition.

The bill, as it stands, leaves the potential for criminal penalties. Labor will now be forced to legislate to fix this.

The workplace relations minister, Tony Burke, accused the Liberals of “trying to expose employers to potential criminal penalties after throwing a pathetic tantrum in the Senate”.

• Sign up for Guardian Australia’s free morning and afternoon email newsletters for your daily news roundup

“Despite the opposition’s idiotic and irresponsible behaviour – we will legislate to fix this,” he said, noting the provision does not take effect for another six months.

The shadow workplace relations minister, Michaelia Cash, said the government’s “rushed and chaotic approach to this bill was on full display today”.

“They were so desperate to get this through today they voted for bad legislation,” she said.

The bill was supported by Labor, the Greens, Lidia Thorpe and David Pocock, after the latter struck a deal simplifying casual conversion and narrowing the application of gig economy reforms.

Employer groups praised Pocock and the Jacqui Lambie Network for their efforts to wind back elements of the bill but have called the new right to disconnect “impractical”.

The right to disconnect will prevent employees being punished for refusing to take unreasonable work calls or answer emails in their unpaid personal time.

The Australian Industry Group chief executive, Innes Willox, said the change is “impractical and will simply add unwarranted conflict and uncertainty into our workplaces”.

Willox said changes were added “at the last moment, without being properly thought through, with a view to securing the Greens’ support for the passage of the rest of the legislation” despite existing protection against unreasonable overtime in the Fair Work Act.

Under the new system, employees will be able to raise a complaint about intrusive phone calls or the expectation they answer work emails out-of-hours with their employer.

If the issue is not resolved at the workplace level, employees can apply to the Fair Work Commission for an order on the employer to stop unreasonable out-of-hours contact. The Coalition is concerned the breach of an order is punishable by fines of $18,000.

On Wednesday the Senate voted to force a final vote on the bill on Thursday afternoon, confirming that Labor had the numbers to secure its passage.

The closing loopholes bill makes changes to the definition of casual employment, and gives power to the Fair Work Commission to create minimum conditions in the gig economy and the road transport industry.

On Thursday Lambie made a last-ditch attempt to add an amendment to help textile workers demerge from the Construction Forestry Mining Energy Union through a secret ballot.

A furious Lambie fronted a press conference in Canberra, accusing the Greens and Labor of being unduly influenced by Victorian construction secretary, John Setka, to prevent the easier demerger procedure.

Lambie said it was “absolutely shameful” that Labor and the Greens would not support her amendment, which was defeated by 31 votes to 30 with their votes and that of Lidia Thorpe.

“Don’t you stand up and talk about women’s rights in that chamber,” Lambie said. “Because as of today in my eyes your credibility has gone down the gurgler.”

Lambie confirmed that she will use the bill returning to the Senate to fix the error about criminal penalties to again push the demerger amendment and, if that fails, move a private senator’s bill.

Setka announced his retirement on Thursday, telling unions delegates he would not nominate to run in elections later this year, a union spokesperson confirmed.

The CFMEU Victoria and Tasmania secretary has been at the helm for more than a decade, during which time he has been involved in multiple workplace controversies and a bitter and public breakdown of his marriage.

• Industrial relations
• Gig economy
• Australian politics
• news