Labor has struck a deal with crossbenchers to split its industrial relations reform in two parts, enabling extra protections for workers to pass on Thursday.
Workplace Relations Minister Tony Burke said the government had secured the support of independent senators Jacqui Lambie and David Pocock for key parts of the "closing loopholes" legislation.
The measures due to pass the Senate by Thursday afternoon would stop companies underpaying workers through the use of labour hire and criminalise intentional wage theft.
As well, there would be a new criminal offence of industrial manslaughter, better support for first responders' post-traumatic stress disorder and improved protections for workers subjected to family and domestic violence from discrimination at work.
The functions of the Asbestos Safety and Eradication Agency would be expanded to include silica.
New laws will stop companies underpaying workers and criminalise intentional wage theft. (Bianca De Marchi/AAP PHOTOS)
And a loophole would be closed in which large businesses claim small business exemptions during insolvency to avoid redundancy payments.
Mr Burke said other measures flagged by the government in its initial larger bill would be examined next year.
"I'm even more optimistic about those remaining provisions because of ... the goodwill and good intentions of the crossbench," Mr Burke said.
Greens leader Adam Bandt said his party's support came after the government agreed to criminalise underpayment of superannuation.
"(We) would have liked to have seen more protections for casual and gig workers before Christmas, but there's some important wins in this bill," he said.
The Greens will also continue to push for the right of employees to disconnect from work to prevent employers contacting staff outside work hours and ensure workers don't have to respond to emails and phone calls outside their shifts.
The government will also boost funding for the small business advisory service in the Fair Work Ombudsman, and will review the Comcare scheme to help workers injured on the job.
This will cover ambulance officers, emergency services communications operators, firefighters, the Australian Border Force and Australian Federal Police.
Kay Catanzariti, whose son was killed at a Canberra work site, welcomed the strengthening of protections after years of advocacy.
"We're all Australians - it doesn't matter what jurisdiction you get killed in," she tearfully told reporters.
Senator Lambie said she had a "gutful" of big companies not paying people what they deserve under labour hire.
"They've got massive profits, these bloody little buggers, and they're not doing the right thing," she said.
ACTU secretary Sally McManus described the announcement as a "cost of living Christmas present" for working people but said the job wasn't done yet.
She remained confident other protections for casual and gig economy workers would also pass.
"The government is just as committed to putting the rest of the bill through," Ms McManus said.
"We look forward to support of people on the crossbench and constructive engagement to finish the job."
She said trade unions supported the right to disconnect, and would urge the government to support the proposal.
Independent senator Lidia Thorpe also signalled she would back the bill.