Government minister Angus Taylor has dismissed the biggest union advertising campaign in a decade as an "act of desperation".
The Australian Council of Trade Unions launched the media blitz on Sunday, the largest since the anti-Work Choices campaign which contributed to the downfall of the Howard government in 2007.
The campaign calls for pay increases for workers and government restrictions on casual employment.
Mr Taylor said the ACTU's claims on workforce casualisation didn't stack up.
"It's an act of desperation by the unions," Mr Taylor told Sky News on Monday.
"Their membership is down to less than 10 per cent of the private sector."
He said under the Turnbull government more than 11,000 jobs had been created with 75 per cent of those permanent roles.
But Labor frontbencher Linda Burney said the union had not overstated their numbers on people being pushed into casual work.
"People are finding putting meals on the table, making ends meet and particularly paying utility bills very difficult," Ms Burney told Sky News.
Casualisation is especially impacting women and young people, Ms Burney said.
"It's very difficult to plan for a future, particularly financially, when your work is totally casualised," she said.
The ACTU will continue the campaign for two months in response to what it describes as a "crisis" of record low wages growth paired with unrestricted causal employment.