A landmark ruling that has granted a casual worker annual leave entitlements has sparked warnings from unions and employer groups that a clearer definition of casual employment is needed.

The full Federal Court of Australia on Thursday found a truck driver employed at a Rio Tinto mine under a labour hire arrangement as a casual, was not a casual under employment law, because of his regular and continuous pattern of work.

Under the Fair Work Act national employment standards, a casual employee is not entitled to annual leave which permanent employees receive. The Act does not provide a definition of a casual employee.

Innes Willox, chief executive of AI Group. Credit:Stewart Donn

The Australian Industry Group said the decision in Workpac v Skene which found Queensland truck driver Paul Skene was entitled to be paid accrued annual leave on termination of his employment was "disappointing" and has asked the federal government to intervene to clarify the law.