Unions have vowed make weekend penalty rates a key federal election issue as pressure mounts for the payments to be cut.
The retail industry argues the higher rates for Saturday and Sunday work are out of step with 2016 workplaces and believes there's a strong case to reduce them.
The stand-off comes as the Fair Work Commission began a week-long final hearing into penalty rates in Sydney on Monday.
Members of the hospitality union United Voice and the Shop, Distributive and Allied Employees' Association (SDA) rallied outside the hearing saying an industry push to cut weekend penalty rates will hurt workers struggling to make ends meet.
"The government has not made clear where it stands in terms of supporting people who work on weekends to continue to receive weekend rates, so we will be taking it to the election," United Voice national secretary Jo-anne Schofield told reporters.
"The community is firmly on-side on this issue.
"People know that this is the beginning of a systemless country where we see people's pay reduced."
The NSW Business Chamber wants a reduction in Sunday and public holiday rates for the retail sector concedes there's a "disability" associated with working weekends.
"Given the social and family activities conducted at these times employees can miss out ... because of work," special counsel Luis lezzo told the hearing.
"What we say however is that the historic assessment of the level of disability associated with Sunday work specifically, and public holiday work, is now out of sync with the experience of real workers in 2016."
The existing regime of penalty rates was disproportionate, he added.
Last year, the Productivity Commission recommended Sunday penalty rates in the retail and hospitality sectors be brought into line with lower Saturday rates.
University student and supermarket worker Harry Gregg said penalty rates were a safety net, not a luxury.
"If I as a student can't earn money on the weekends, I can't afford to study during the week," he told reporters.
"Not every student has their parents paying everything for them."
Aged care nurse Margy Scott said she and her colleagues aren't well paid as it is.
"It (cutting penalty rates) brings our wages down dramatically," she said.
The hearing continues.
