Shares of BHP Group (ASX:BHP) was flat with a slight negative tilt in Monday trade, while shares of Boss Energy (ASX:BOE) and Deep Yellow (ASX:DYL) fell 1% and 2%, respectively, after a Sunday report by The Australian said a group representing the miners had filed a formal complaint with the Fair Work Ombudsman against the Electrical Trades Union (ETU).

The Minerals Council of Australia alleges the ETU sent emails to employers claiming that the use of labor hire workers in equivalent roles to employees breached "same job, same pay" laws, per the report.

The group also accused the ETU of making false and unlawful claims and misrepresenting workplace rights.

The ETU did not immediately respond to a request for comment from MT Newswires.