Hundreds of thousands of low-paid workers would get protection from being underpaid, under a push to plug legal loopholes being exploited by big companies such as KFC and McDonald's.
On Monday the Greens will introduce its Pay Protection Bill into Federal Parliament in a bid to change the Fair Work Act.
The move comes in response to the massive wages scandal involving deals between Australia's biggest employers and the Shop, Distributive & Allied Employees Association (SDA).
A Fairfax Media investigation revealed those deals left more than 250,000 workers paid less than the award – the wages safety net – and saved big business more than an estimated $300 million a year.
Greens employment and industrial relations spokesman Adam Bandt said his bill would ensure that workers on collective agreements were always paid above the wages safety net.
"An 18-year-old working nights at McDonald's shouldn't be getting paid less than the legal minimum wage," Mr Bandt said. "If the law allows deals to be done that underpay our lowest paid workers, then the law needs to be fixed."
Mr Bandt said he expected bipartisan support as "the basic principle that an employer shouldn't be able to pay someone less than the legal minimum wage is unobjectionable".
But the proposed changes are potentially difficult for Labor as they involve the conduct of its largest affiliate, the conservative SDA.
ACTU president Ged Kearney said it welcomed any initiative that "will stop Australian workers falling below the pay they are entitled to.
"While the unions were not consulted on the proposed changes to the [Fair Work] Act, we welcome any attempt to ensure that workers' rates of pay are not eroded over time."
The Greens' bill would ensure that workers on collective agreements have their pay compared to the minimum full rate of pay in the award – which includes casual loadings and penalty rates – rather than just the minimum base hourly rate.
Fairfax Media reported in August that a Hungry Jack's agreement with the SDA paid no penalty rates and casual rates below the award while base hourly pay was just above. That resulted in some Hungry Jack's workers being paid 30 to 40 per cent less than the award or as much as $5000 a year.
Josh Cullinan, from the new Retail and Fast Food Workers Union, and who helped expose the wages scandal, said the proposed bill was a "watershed" and it was now up to politicians to decide where they stood.
"Every day that politicians equivocate on this important legislation our members are losing $1 million a day," he said. "It's gotta stop."
Major employers including McDonald's, Coles and Woolworths all pay significant numbers of workers less than the award through reduced, or in the case of McDonald's no, weekend penalties.
"These huge corporations are not short of a quid. At a very minimum they can afford to pay the basic legal minimum to people working late at night or on weekends," Mr Bandt said.
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