Casual employees and qualifying for unfair dismissal remedies

The true nature of the relationship of employer and casual employee was at the heart of Shortland v Smiths Snackfood Co Ltd (2010) FWAFB (2010) FWA 2826 in which the Full Bench considered the matter this way in a common law context:
As a matter of the common law of employment, and in the absence of an agreement to the contrary, each occasion that a casual employee works is viewed as a separate engagement pursuant to a separate contract of employment. Casual employees may be engaged from week to week, day to day, shift to shift, hour to hour or for any other agreed short period.4 In this sense no casual employee has a continuous period of employment beyond any single engagement. Moreover, it is common for a casual employee to transition between a period in which their engagements with a particular employer are intermittent and a period in which their engagements are regular and systematic and vice versa.