The decision of the commission will affect thousands of workers in the industry and could see employers pay out more than $1 million to sacked workers, according to the union.

The action will be brought against Kentz Australia, the principal electrical contractor on the Northern Territory’s Inpex Ichthys project, but will affect FIFO employees nationwide, ETU acting national secretary Michael Wright said.

The practice of giving workers notice on the last day of their swing had become widespread as the mining boom dissipated, he said.

“We are seeing workers who endure extremely difficult conditions now being denied the wages that are owed to them under the Fair Work Act. Contractors are looking to wring every dollar they can out of their workforce,” Wright said.

“This practice is underhanded and unethical, and we are determined that workers who are laid off from FIFO projects will be paid what they are owed.”

The case is expected to directly affect 150 former workers at Inpex but will flow on around the country. If successful, the case will result in payments totalling more than $1 million to Inpex workers.

Workers on other projects in the Northern Territory, Western Australia and Queensland are among those who stand to receive payments should the commission side with the union.

“We have seen a once-in-a-generation resources boom in Australia. It is a matter of fundamental decency that workers who built the infrastructure that enabled this boom not be given the short end of the stick as this boom winds down,” Wright said.