The commission handed down a decision last week defeating reforms to the government's omnibus bill giving permanency to casual workers.

Shadow industrial relations minister Tony Burke said the case exposed problems with the legislation.

"We've always said you could drive a truck through (the laws), and a truck just went straight through," Mr Burke told reporters in Canberra on Wednesday.

Mr Burke said the government was never serious about wanting to deliver secure employment for casual workers.

"When they were first talking about casual conversion laws, they were never serious about delivering security. They wanted to virtue signal, claiming that they've done something. The case shows they've done nothing," he said.

The FWC case was the first time new casual conversion laws introduced in 2021 were tested.

The new laws require employers to offer casual workers permanency if they have been employed for a minimum 12 months, where six of those months have been worked in a regular pattern.

The case denied Mr Toby Priest, a casual academic tutor at Flinders University for over a decade, conversion to a permanent part-time position.

The decision turned on provisions in the Fair Work Act requiring the conversion to be "without significant adjustment," a test that Mr Priest fell short of.

The conversion laws also enable employers several "reasonable grounds" to not make an offer to transition casual workers into permanent roles.

Mr Burke said Labor would address the issue through their secure jobs plan.

"Our secure jobs plan is a pathway announced last year that creates the opportunities where we deal with some of the rorts that have been undercutting job security," he said.

Labor's plan will include legislation creating an objective test to classify casual workers.

The author has written this story in a personal capacity.

Australian Associated Press