Under the Environment Protection and Biodiversity Conservation Act 1999 (Cth) (EPBC Act), an action includes a project, a development, an undertaking, an activity or series of activities, or an alteration to any of these things [s 523]. An action could be construction, expansion, alteration or demolition of buildings, structures, infrastructure or facilities, mineral and petroleum resource exploration and extraction, waste disposal, earthworks, vegetation clearance, aquaculture, and other dealings with land [see Significant Impact Guidelines 1.1 - Matters of National Environmental Significance].

An action is not the granting of a government approval [s 524]. For example, the need for an export licence, or the provision of Commonwealth funding, does not itself trigger the operation of the Act. This distinguishes the arrangements under the EPBC Act from earlier Commonwealth controls which were often targeted at funding or approval mechanisms to trigger environmental assessment.