(1) Subject to section 61 and section 62, the authority may vary an environmental authorisation by written notice to the holder of the authorisation—
(a) on application by the holder; or
(b) if this Act has been amended since the authorisation was granted; or
(c) if the authority has reasonable grounds for believing—
(i) that—
(A) in conducting the authorised activity, the holder has contravened, is contravening or is likely to contravene the environmental authorisation, an environmental protection order or a provision of this Act; and
(B) as a result, serious or material environmental harm has happened, is happening or is likely to happen; or
(ii) that the potential for the authorised activity to cause serious or material environmental harm has changed; or
(iii) that the circumstances in which the environmental authorisation was granted or previously varied have changed in a material respect; or
(iv) that the environmental authorisation was granted or previously varied on the basis of false or misleading information.
(2) The authority may not vary the term of an environmental authorisation under this section.