Malcolm Turnbull has challenged Labor to prove a cleaner's pay will be reduced under proposed penalty rate cuts.
Melbourne hotel cleaner Margarita Murray-Stark was brought to Canberra on Thursday as part of a union campaign to stop penalty rate cuts for low-paid workers.
Ms Murray-Stark told reporters she earned about $30,000 a year, and a cut to penalty rates would mean she would earn $2000 less.
"We only want a decent life and a decent wage ... (and) we are unrespected by the prime minister," she said.
The mother of two is featured in a full-page advertisement in The Australian newspaper after a crowd-funding campaign #meetwithmargarita resulted in 700 people donating over $20,000.
Asked about her case in parliament, Mr Turnbull challenged Labor leader Bill Shorten to prove Ms Murray-Stark's claim about a $2000 a year cut.
"We understand the battle that Margarita has," Mr Turnbull said.
"And we applaud her, as a widow, working hard."
He then gave Mr Shorten a chance to assure the parliament Ms Murray-Stark's employer had confirmed her pay would be cut.
But Speaker Tony Smith shut it down, saying it was not in the rules for the opposition leader to answer questions in question time.
Mr Shorten later told parliament Mr Turnbull had "no idea how ordinary Australians live their lives".
"Why should Margarita have to negotiate to keep her penalty rate? Why do people who have a minimum wage and a penalty rate as a right have to renegotiate for something that was already theirs to begin with?"
The Fair Work Commission's decision is yet to be rolled out for modern award workers in the retail, hospitality and pharmacy sectors while it considers the timing of the cuts.
Labor, Greens and the crossbench on Thursday joined forces to pass a private bill to stop the decision.
The bill now heads to the lower house where it's likely to be defeated, given the coalition holds a slim majority.
The commission is also working on its minimum wage decision.
Australia's peak trade union body the ACTU is seeking a $45 a week rise in the minimum wage.
Labor declined to put a figure in its submission, but said it supports a "strong and appropriate minimum wage".
Asked why Labor did not propose a figure, Mr O'Connor said his party had always taken the approach of talking about the "principles underpinning the need for a wage increase".
The Turnbull government said in its submission the commission should take a "cautious approach, taking into account the uncertain economic outlook and the need to boost employment and job creation, particularly for young people and the low-skilled".
The Australian Industry Group is arguing for a modest wage increase of 1.5 per cent.
The current minimum wage is $17.70 an hour, or just under $35,000 a year for a full-time worker.
