The Mining and Energy Union will launch an advertising campaign to support the Federal Government's proposed Same Job Same Pay laws for labour hire workers on Wednesday.
It comes as mining giant BHP warns that the legislation would cost the company up to $1.3 billion annually and result in job losses.
The MEU print, television and social media campaign will continue until the new laws pass Parliament.
Hunter Valley coal mineworker Rebecca McDonald, who is in Canberra for the campaign launch, said about a third of her 100 member production crew were employed by labour hire companies.
"Once they've finished training, contractors do the same work as permanent workers but they are paid much less and they miss out on the entitlements available under our Enterprise Agreement," she said.
"Labour hire workers fear that if they join the union, take leave or raise a safety concern, they will never get a permanent job.
"I was labour hire for about five years and it was exhausting and demoralising."
MEU general secretary Grahame Kelly said that despite mining company fearmongering, Same Job Same Pay laws would be good for the industry.
"Mining companies are notorious for throwing their weight around when governments propose changes requiring them to act in the community's best interests.
"But Same Job Same Pay will be a positive for mining because it will end a rort affecting the workers and regional communities that sustain the industry.
"Same Job Same Pay will improve wages and conditions for labour hire workers and prevent them being treated as second class citizens. It will strengthen collective bargaining by ensuring companies stick to their end of the bargain. And it will be great for regional communities who lose out when big employers cut wages for half the workforce."
In its submission, BHP said that it supported the government's objective to protect low-paid and vulnerable workers from exploitation. However, it was concerned that the policy in its current form would have serious impacts on operations, jobs and regional training programs. This, in turn, would impact Australia's competitiveness and productivity.
But the union says mining companies have replaced thousands of permanent jobs with insecure, lower-paid labour hire jobs, cutting wages while their profits have grown.
Mr Kelly said Same Job Same Pay laws would close the loophole that allows companies to avoid paying the wages and conditions negotiated under site enterprise Agreements by outsourcing jobs to labour hire companies paying barely above the legal minimum.
The practice means that on many mine sites, labour hire workers are paid from $30,000 to $50,000 a year less than permanent workers for doing the same job. Workers in other industries including transport and manufacturing are also affected.
"We know that workers in industries apart from mining are also the victim of labour hire loopholes, being paid less than permanent employees performing the same job," Mr Kelly said.
"We encourage all workers who want to end this rort to get on board and help make sure Same Job Same Pay becomes a reality."
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