The Federal Government says foreigners working on offshore oil and gas projects are being forced to stop work after the Senate killed off a new visa regime.

Last night Labor, the Greens and the Palmer United Party teamed up in the Senate to stop foreign workers being employed on maritime crew visas.

Assistant Minister for Immigration Michaelia Cash says the foreign workers will now have to down tools, and that could have flow-on effects for other workers.

"Labor senators knowingly placed thousands of Australian jobs at risk," she said.

Labor and the Greens had the support of Democratic Labour Party senator John Madigan, Australian Motoring Enthusiast senator Ricky Muir and the three Palmer United Party senators - including Jacqui Lambie, who said the regulation applied to workers on ships that were permanently in Australian waters, adding they should have their full conditions protected.

"The rates of pay of these seafarers are so low that it will be impossible for vessel operators to ignore the option of employing overseas workers within Australia's exclusive economic zone," she said.

Paddy Crumlin from the Maritime Union of Australia said the maritime crew visa was a loophole being used to exploit workers.

"It was here to bring in Filipino, Indonesian seafarers, not on Australian wages and conditions," he said.

Senator Cash said she was seeking urgent advice from the Immigration Department.

"We will currently have people who are literally on vessels or potentially on rigs, who had temporary visas up until the disallowance motion went through, who if they now undertake the role that they are being paid to do will be in breach of their temporary work conditions," she said.

"Will the contracts that these companies have be able to be discharged? I don't know."

Senator Cash dismissed the view that the regulations allowed workers to be paid less than Australian standards as "propaganda" by the Maritime Union, which she called the most militant union in Australia.

Government can issue quick fix, says Bandt

Greens industrial relations spokesman Adam Bandt said Senator Cash could easily ensure that everyone affected could keep working.

"The minister can issue a new regulation that says people who are working in offshore oil and gas can continue to do it if they're from overseas," he said.

"It just means that the basic floor that applies is Australian wages and conditions. You can't undercut that."

Fifield accuses Greens, Labor of delaying carbon tax repeal

The disallowance motion has demonstrated that the Government cannot take anything for granted in the Upper House at the moment.

The Manager of Government Business in the Senate, Mitch Fifield, accused the Greens and Labor of a deliberate go-slow on the carbon tax debate.

He said they spent three-and-a-half hours on one amendment.

"That is not acceptable. It is seeking to delay the inevitable, seeking to defy the will of the Australian people expressed through the ballot box," he said.

"We will use the full avenues available in the Parliament to ensure the carbon tax is repealed."

He said a gag motion could be used to cut off debate.

"There are a range of parliamentary procedures which are available and we will use those to best advantage to make sure the carbon tax is repealed," he said.

Senator Fifield hinted he could have the support of crossbenchers for a gag motion.

"Parliamentarians have had their say over 50 hours of debate with the three presentations of the repeal package to the Senate ... and the interesting thing is that actually everyone knows what their position is," he said.

"It's time to vote. It's time to repeal the tax."

Senator Fifield also reiterated the Government's determination to have a vote on the mining tax repeal bill.

"If the Senate needs to continue for an additional day to make sure that we vote on the repeal of the mining tax then that's what will happen," he said.