The union fears the airline is planning to cut 2,500 jobs and export the jobs to China.
The union's secretary, Doug Cameron, says the company's maintenance workers are the people who gave Qantas its reputation for safety.
Mr Cameron says cutting their jobs is not the way to reward them.
"We've got a Chief Executive Officer on a salary of about $6.1 million and that should be the first place they look at some cost-cutting.
"It's absolutely outrageous that ordinary Australian workers are being brought to book by people who are earning $6.1 million, who are telling workers on $45,000 that they're earning too much and costing too much.