The Construction, Forestry, Mining and Energy Union in Australia is up in arms over plans for more foreign workers in the minerals sector.
Approval has been given by the federal government for 1700 overseas workers will work on the $A9.5 billion Roy Hill project in Pilbara, Western Australia
The CFMWU fears they will displace Australian workers and do on on lower wages.
The move could be repeated in Queensland, where 3500 personnel are needed to build a coal mine in the southwest of the state.
The ABC reports the $A6.4 billion Alpha coal project has been given conditional approval by the Queensland government and now needs federal approval to proceed.
If and when the mine is built, Queensland Premier Campbell Newman says his priority will be for it to employ locals.
Deputy Premier Jeff Seeney told the State parliament that Alpha, an open-cut coal mine, would produce 30 million tonnes per year.
He said the project will create 3500 construction jobs and 1000 operational positions and will inject $A1 billion into Queensland's economy each year.
Alpha is owned by Gina Rinehart's Hancock Coal.
The federal Labor caucus on Tuesday passed a resolution ensuring Australian workers are helped to get mining industry jobs.
The ABC reports 17 MPs spoke about the resolution, including Treasurer Wayne Swan and Immigration Minister Chris Bowen.