The Agency's mandate is twofold. It is required to carry out federal responsibilities in relation to the pipeline and facilitate the efficient and expeditious planning and construction of the pipeline taking into account local and regional interests, in particular those of native people. It is also responsible for maximizing the social and economic benefits from the construction and operation of the pipeline while at the same time minimizing any adverse effect on the social and environmental conditions of the areas most directly affected by the pipeline.

The Agency was designed to act as a single window between federal authorities and the Foothills Group of Companies, and between provincial and territorial governments, and the Government of the United States. In keeping with the Act, many regulatory powers of other federal departments and agencies related to the pipeline project have been delegated to the Agency. This is not the case for those powers reserved exclusively to the National Energy Board or shared between the Board and the Agency.