Dunia Elkazzi's modest income as a cleaner in Sydney's CBD means she often struggles to pay for the medicines her sick parents need.
An extra $26 a week would help make ends meet, says Ms Elkazzi, who lives in Bankstown in Sydney's southwest.
"It's very hard. I'm looking after my parents. You've got to pay the bills, buy the food. Everything is up," she told reporters.
Unions insist that employers can afford a $26-a-week pay rise for minimum wage workers.
But they're prepared for a fight, with ACTU secretary Jeff Lawrence lodging a submission with Fair Work Australia (FWA) for the lowest wage earners to take home $615.30 a week from July.
Mr Lawrence said a 68-cents-an-hour increase would help stem the widening gap between Australia's 1.4 million low-paid workers and the rest of the workforce.
But the push for a pay rise was likely to meet resistance, Mr Lawrence said.
"I would expect that the employers, as they usually do, will say, 'Shock and horror, the economy can't afford this'," he said.
"It's absolute rubbish.
"The ACTU actually doesn't make ambit claims or outrageous claims in these minimum wage cases."
Mr Lawrence is due to step down from his role in May, a month before FWA hands down its annual decision affecting retail, hospitality and aged-care workers.
Last year, the ACTU pushed for low-wage workers to be given a $28-a-week pay increase but FWA granted a smaller $19.40 rise, taking their weekly package to $589.30.
The Australian Chamber of Commerce and Industry (ACCI) said past increases to the minimum wage had been hard on business.
The ACCI favours a $9.40-a-week pay increase, a level slightly below last year's $9.50 submission to FWA's annual wage review.
"In 2012 it is time the voice of Australian business was heard loud and clear, particularly the voice of those award-reliant businesses struggling in the slow lane of the Australian economy that bear the brunt of these annual wage review decisions," the chamber said in a statement.
The Australian Council of Social Service (ACOSS) declined to nominate a figure but said any pay rise needed to recognise that about one in five minimum wage workers lived below the poverty line.
Mr Lawrence said he was confident his likely successor, Dave Oliver, the current national secretary of the Australian Manufacturing Workers Union (AMWU), would be in a good position to present the ACTU's minimum wage case.
"The ACTU will continue to make these claims, to continue to argue these cases, next year, the year after, 10 years' time ... irrespective of who's secretary," he said.
