(1) The powers under sections 48 and 49, paragraph 50(a) and sections 53 and 54 may be exercised only as provided in this section.
(2) The powers may be exercised in relation to:
(a) a person holding, or performing the duties of, an office or appointment under a law of the Commonwealth or of a Territory; or
(b) a Commonwealth authority.
(3) The powers may also be exercised in relation to any person for the purposes of an inquiry to the extent that the subject matter of the inquiry relates to a subject of Commonwealth power.
(4) Subsection (3) does not enable a power to be exercised to the extent that it would impair the capacity of a State to exercise its constitutional powers.