Although it is part of core government business to collect information about its citizens, ‘big data’ has increased the scale, speed and complexity of data collection and use to such an extent that it is arguably qualitatively different from the record-keeping that has gone before it. Big data represents a radical shift in the balance of power between State and citizen. This article argues that embedding big data in government operations masks its deployment as enhancing government power, rather than simply facilitating execution of government activities. In other words, big data is ‘disruptive’ technology that calls for the examination of the limits of government power. To illustrate this argument, this article examines a selection of recent case studies of attempts by the Australian government to deploy big data as a tool of governance. It identifies the risk to the citizen inherent in the use of big data, to justify review of the bounds of government power in the face of rapid technological change.