Industrial Relations Minister Kelly O'Dwyer has dismissed claims casual workers are being denied a premium despite trading off leave and other entitlements.
Australian Council of Trade Unions research has argued many casuals get between two and five per cent more than their permanent counterparts, rather than the usual 25 per cent loading.
But Ms O'Dwyer rejected suggestions many casual workers were receiving just five per cent more than permanent employees doing the same job.
"In many awards, many modern awards you actually receive a 25 per cent loading in lieu of your other entitlements such as holiday and sick pay," the minister told the National Press Club in Canberra on Tuesday.
She said many employees and businesses preferred the flexibility of casual work.
"I believe it's important to give people flexibility in the way that they work, in the way that they manage their lives," Ms O'Dwyer said.
The union movement is also campaigning for 10 days' paid family and domestic violence leave after labelling Ms O'Dwyer's move to allow victims early access to superannuation as inadequate.
ACTU president Michele O'Neil said a leave entitlement was vital for women escaping violence.
"In 2018 women escaping violent relationships should not have to choose between their income and their safety. And they should not have to spend their retirement savings or take on debt," Ms O'Neil said.
"Our broken system already sees women retire with 47 per cent less than men. Forcing women to dip into their super is likely to make worse women's already inadequate retirement savings."
Ms O'Dwyer said the government would let the Fair Work Commission decide, backing its ruling to grant five days' domestic violence leave.
She said after many hearings and more than 500 pages of evidence the ACTU was unable to convince the commission 10 days' leave was needed.
