Australia and New Zealand share a common experience of casual work. In both countries a category of 'casual' has long been permitted under labour regulation, and in both countries this has been associated with concerns about precariousness in employment. At least up until the recent period, labour regulation in both countries sought to limit casual employment in similar ways through quantitative restrictions and through prescription of a 'casual loading' on the hourly rate of pay. Yet, in spite of these strong parallels, casual employment seems less significant in New Zealand as a proportion of the total workforce and it seems to lack the same pace of growth as in Australia. This article asks why there should be this difference. It sketches out an answer that focuses on employer calculations and choices (within the framework of labour regulation, including custom and practice). We suggest that the relative advantages of casual employment to employers are narrower and less imposing in New Zealand. We warn that this cannot be taken as a source of comfort about the better quality of work in New Zealand. The compression of relative advantages is partly because of the greater access of casual employees to standard rights or benefits but it is also partly because of the poorer conditions of permanent workers.