A UNION push for a $30-per-week increase to the minimum wage has been described as a "raid on the payrolls" of Australia's small businesses.
The Fair Work Commission began taking evidence in Melbourne on Tuesday as part of its annual minimum wage review.
Last year, the FWC granted Australia's lowest paid workers a $17-per-week pay rise to $606.
The Australian Council of Trade Unions is pushing for a $30 boost this year, arguing last year's rise was absorbed by business without hurting the economy.
ACTU president Ged Kearney said wages of low-paid workers had fallen from 50% of average weekly full-time earnings in 2000 to 43.4%.
"A $30-per-week rise would be a moderate, affordable increase that will stop 1.5 million workers from falling further behind," Ms Kearney said.
"Wages growth has been steady but not excessive across the economy and inflation is low. Now is the time to look after the urgent needs of low-paid workers."
Ms Kearney said the $30 per-week-rise would directly benefit 745,000 workers. The ACTU is simultaneously seeking a 4.2% pay rise for a further 792,000 award-reliant workers.
But the Australian Chamber of Commerce and Industry has called on the FWC to increase the minium wage by no more than $5.80, an amount Ms Kearney described as "pitiful" and "hardly enough to buy lunch".
ACCI chief executive Peter Anderson said Australia's two million small businesses were "under just as much, if not more, cost pressure as lower paid workers".
"Many are themselves low-paid given the low profits and long hours they and family members devote to their business," Mr Anderson said.
"Today is a chance for the Fair Work Commission to not be seen by small business as the (Un)fair Work Commission, by deciding only a modest rise, allowing carve outs for businesses without capacity to pay, and allowing employers to specifically offset any amount ordered by .25% to fund the July 1 payroll rise in the compulsory superannuation levy."
If the ACTU was successful in securing its $30 increase, Mr Anderson said it would "weaken business viability, reduce profitability and cost jobs".
He said the "alarming" budget forecast of weaker growth and higher unemployment next year supported the ACCI's position.
Neither the ACTU nor ACCI altered their claims in the wake of last week's budget.
The FWC is expected to hand down its decision next month.
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