The government's push to have new workplace laws in place before Christmas has been dealt a significant blow.
The opposition teamed up with the crossbench in the Senate to set the reporting date of an inquiry into the laws that would close labour hire loopholes as February 1.
The laws are aimed at ending exploitative practices such as companies using labour hire workers to undercut the rate of pay agreed for employees.
They also seek to criminalise wage theft, bolster protections for gig workers, create a pathway for casuals to become permanent, and end discrimination against survivors of domestic violence.
The government wanted the inquiry to report in November so it had time to introduce legislation in the upper house in December, before parliament breaks for the year.
Opposition workplace relations spokeswoman Michaelia Cash said it was the duty of the Senate to adequately scrutinise legislation.
"If you were given 800 pages of complex legislation that was going to affect your business, would you not ask the government to actually give this chamber the opportunity to properly scrutinise it?" she told the upper house on Thursday.
Senator Cash said Labor had promised to be a transparent government and businesses needed time to understand the impact of the legislation.
Employment Minister Tony Burke hit back, saying the coalition had voted to delay pay increases, minimum standards for gig workers, insecure work for casuals and the criminalisation of wage theft.
"They spent their entire time in government keeping wages low and holding workers back and they're still at it," he said in a statement.
The opposition and business groups say the laws will hurt the bottom line of small businesses, leading them to hire fewer employees.
AI Group chief executive Innes Wilcox said a comprehensive inquiry was essential given the bill contained "fatal flaws".
"The proposals will not create a single job, do nothing to boost productivity, and will stifle innovation and create insecure work for tens of thousands of Australians who are currently comfortable with their employment arrangements," he said.
The Australian Retailers Association also criticised the laws.
"We need to be extremely careful with any policy changes that could potentially drive price increases or result in added complexity for businesses," CEO Paul Zahra said.
Finance Minister Katy Gallagher said an extended reporting date would not change the coalition's staunch opposition to the workplace laws and the inquiry provided enough time for people to get across the details with assistance from the public service.
She said the opposition's push was a filibuster so the legislation would not be debated on the floor of the Senate and ultimately delay its passing.
The opposition's extension passed 33 votes to 32 after garnering the support of crossbenchers.
Labor and the Greens voted against the extension.
Greens leader Adam Bandt said it was important legislation that would allow workers to get a fair pay rise and the proposed time frame for the inquiry had been "reasonably consistent" with other inquiries.