ONA assesses and analyses international political, strategic and economic developments for the Prime Minister and senior ministers in the National Security Committee of Cabinet. It was established by the Office of National Assessments Act 1977 as an independent body directly accountable to the Prime Minister. The Director-General of ONA is an independent statutory officer who is not subject to external direction on the content of ONA assessments.
ONA bases its assessments on information available to the Australian Government from all sources, both inside and outside the Government. It draws on information provided by other intelligence agencies, as well as diplomatic reporting, information and reporting from other government agencies, and material available from open sources such as news media and publications. ONA also consults broadly within government and with experts in other sectors.
In April 2005, the Open Source Branch (OSB) (now the Open Source Centre) was incorporated into ONA. The role of the Open Source Centre is to collect and validate information from open sources and produce reports based on this information for ONA and other Australian and allied government agencies.
The ONA Act also charges ONA with responsibility for coordinating Australia's foreign intelligence activities and issues of common interest among Australia's foreign intelligence agencies. ONA is also responsible for evaluating the effectiveness of Australia's foreign intelligence effort and the adequacy of its resourcing.