The ruling from the Fair Work Ombudsman, which came into effect on October 1, states a person working as a regular casual employee for 12 months may request for their employment to be converted to full-time or part-time.
For full time work, this would be working an average of 38 hours or more per week across the year, while those working less than 38 hours on average per week can request permanent part-time.
Australian Council of Trade Unions ACTU President Michelle O'Neill has welcomed the changes, saying every employee should be able to have secure work.
"Some people will say 'no I want to stay as a casual'. This doesn't oblige you to convert to permanent if you want to stay as a casual," she said.
"But the majority of workers that we find and the majority of union members are really looking for the security of permanent employment. And this is a very important change."
Employers can refuse an employee's request to make the position permanent, but an explanation of the decision based on reasonable grounds must be provided.
Those reasonable grounds could include situations like the job will no longer existing in the next year, or that making the change to a permanent position would involve a significant increase in the hours of work.
Employers are also required to consult with their employees before refusing the request for a permanent position.
Casual work does not have a precise definition in legislation, but generally includes work arrangements where there is no paid annual leave or sick leave.
