Opposition Leader Bill Shorten says that Labor would consider changing the rules that guide the Fair Work Commission (FWC), if their upcoming decision on the fate of Sunday penalty rates left low-paid workers worse off.

In a speech at the opening of the John Curtin Research Centre in Melbourne last night, Shorten said Labor would not look to legislate for penalty rates, but would consider “changing the rules which guide the exercise of the commission’s discretion”.

“If the rules allow the independent umpire to cut the safety net, leaving hundreds of thousands of low paid Australians with less in their pay packets then the rules need fixing,” he said.

“If the Fair Work Commission backs a cut to cut weekend penalty rates, Labor will ensure that the modern awards are a safety net Australians can continue to rely upon.”

Shorten stopped short of committing to the Greens 2016 election proposal to legislate a floor under penalty rates, saying that legislating for penalty rates would be impractical and limit bargaining.

He did, however, argue that employers avoiding bargaining has become the new normal in many work places, outlining concern for the growing number of workers on award wages.

“[Retail] is focused on reducing wage costs, not boosting productivity…­­­­the ability of corporations to cut the paying conditions of workers is increasingly prevalent and increasingly worrying to Labor,” Shorten said.

Australian Retailers Association (ARA) chief Russell Zimmerman has criticised the speech, telling Inside Retail that Labor has now applied renewed political pressure to the FWC’s upcoming decision, which was delayed last year and is now expected in February.

“The Labor government is now going against what it set up as an independent tribunal and is trying to influence it,” he said.

The ARA is lobbying, alongside the Master Grocers Association (MGA) and the Franchise Council of Australia (FCA), for a reduction in Sunday penalty rates, citing the inability of businesses to employ more staff as a result of the costs.

Zimmerman, who is seeking to have rates reduced from double time to time-and-a-half, believes that the issue has become so bad that Australian retailers are risking becoming uncompetitive with their overseas counterparts.

“We are hopeful that the decision will rebalance penalty rates to sustainable levels, allowing employers to expand operating hours and drive additional employment within the retail sector.”