Casuals have unfair dismissal rights in these circumstances

In Ponce v DJT Staff Management Services Pty Ltd T/A Daly’s Traffic Roe C observed (2010)FWA 2078
“It is the employment which must be on a regular and systematic basis. This does not mean that the hours or days of work must be regular and systematic. Although the previous legislation referred to the period or periods of casual engagement rather than the period of casual employment I do not think that this change is of much practical significance. The previous authorities have also established that employment or engagement can be regular and systematic even if it is seasonal, or where the times and dates of work are quite irregular or are not rostered, or where there are breaks due to school holidays or other needs of the employee. In Summerton v Jabiru Golf, the hours worked varied from 3 to 39 in a week but it did not stop SDP Duncan finding that the employment was regular and systematic. It is clear that to establish “regular and systematic” there must be sufficient evidence to establish that a continuing relationship between the employer and the employee has been established. This is clearly a reason why there is a legislative requirement for a reasonable expectation of continuing employment.” (citations omitted)
“Full-time, part-time and casual employees often work on varying days and at varying times. Awards provide wide flexibility in this respect and further flexibility is available through flexibility agreements and through collective agreements. Under many awards ordinary hours can be averaged over a week, a month or sometimes longer periods; ordinary hours under many awards can be worked on any day of the week, and daily hours for full-time workers can vary under many awards from 4 to 12 hours. The fact that an employee works more hours in one week or one month than another and the fact that an employee might have variable start and finish times is not conclusive evidence of irregular, occasional, or non-systematic employment or engagement.”
“I find that there was a clear pattern of work being offered with reasonable frequency and of the work being generally accepted. I find that work was being offered generally when it was available and that periods when work was less intense were generally when work was not available. I find that the employer had a reasonable expectation that Mr Ponce would work when work was offered. The pattern of offer and acceptance could not be described as informal, irregular or occasional. This is sufficient to find that the period of casual employment was on a regular and systematic basis.”