4Object of Act

4  Object of Act  (1) The object of this Act is to regulate, in the national interest, the coming into, and presence in, Australia of non‑citizens.  (2) To advance its object, this Act provides for visas permitting non‑citizens to enter or remain in Australia and the Parliament intends that this Act be the only source of the right of non‑citizens to so enter or remain.  (3) To advance its object, this Act provides for non‑citizens and citizens to be required to provide personal identifiers for the purposes of this Act or the regulations.  (4) To advance its object, this Act provides for the removal or deportation from Australia of non‑citizens whose presence in Australia is not permitted by this Act.  (5) To advance its object, this Act provides for the taking of unauthorised maritime arrivals from Australia to a regional processing country. 4AA  Detention of minors a last resort  (1) The Parliament affirms as a principle that a minor shall only be detained as a measure of last resort.  (2) For the purposes of subsection (1), the reference to a minor being detained does not include a reference to a minor residing at a place in accordance with a residence determination. 4A  Application of the Criminal Code