The following is an extract from the DIBP policy manual:
DIBP is responsible for identifying each person who crosses Australia’s border. This role is unique among Australian Government agencies. It involves establishing the identity of people born outside Australia (that is, non-citizens), to a sufficient standard to grant permission to enter and remain in Australia for the period of time and purpose authorised by their visa. The department fulfils this responsibility to ensure it can effectively deliver Australia’s visitor, migration and citizenship programmes, while preventing the entry of persons who may seek to threaten the national interest.
When short, medium and long-term visits and migration to Australia are reduced to core elements, they are about identity and intent. Is the person who they say they are? Are they coming to Australia for the lawful purpose authorised in their visa?
The department has a national responsibility to ensure that high standards of integrity apply to identifying non-citizens. Accurately establishing identity is the prerequisite for all security, character and immigration checks. There may be serious consequences if the department gets identity “wrong”.
To achieve these objectives, Australia is increasingly using biometric data in visa processing. Not all visa applications and not all visa applicants are subjected to biometrics. There is a current list of countries to which it applies and to the visa subclasses to which it applies on the DIBP website. See also the following: http://www.immi.gov.au/allforms/biometrics/offshore/