Underpayment is rife among migrant workers in Australia with many not reporting the issue due to fears of deportation, a new report has found.
The Unions NSW audit, released on Monday, showed more than 60 per cent of job advertisements reviewed in the nation's top eight industries offered illegal rates of pay.
More than one-third of migrant workers surveyed also reported being paid or offered a lower salary because of their visa type, while more than one quarter received lesser salaries because of their nationality.
Unions NSW is using the latest findings to call for greater protections for migrant workers.
"Our audit exposes this underbelly and demonstrates the need for the commonwealth to bolster its efforts to stamp out bad employer behaviour while empowering workers to enforce their rights," secretary Mark Morey said in a statement.
"The visa system is broken and needs reform to strengthen the protection of migrant workers.
"Right now, too many workers remain shackled to their employers due to the uncertainty of their visa status."
Unions NSW wants there to be a firewall between the Fair Work Ombudsman and the Department of Home Affairs so vulnerable workers can act against unscrupulous employers.
It also wants a new substantive visa to allow workers with outstanding claims for workplace entitlements to remain in the country with working rights until their claim has been settled.
Immigration, Citizenship and Multicultural Affairs Minister Andrew Giles will join the union on Monday to launch the new report.