(1) Subject to section 144, application may be made to the AAT for review ( AAT first review ) of:
(a) a decision of the Secretary, the Chief Executive Centrelink or an authorised review officer made under section 126 or 135; or
(b) a decision under this Act made personally by the Secretary or the Chief Executive Centrelink.
(4) For the purposes of subsection (1), the decision made by the Secretary, the Chief Executive Centrelink or the authorised review officer is taken to be:
(a) if the Secretary, the Chief Executive Centrelink or the authorised review officer affirms a decision--that decision as affirmed; and
(b) if the Secretary, the Chief Executive Centrelink or the authorised review officer varies a decision--that decision as varied; and
(c) if the Secretary, the Chief Executive Centrelink or the authorised review officer sets a decision aside and substitutes a new decision--the new decision.