As has been the practice in New Zealand when a Commission of Inquiry
consists only of or is chaired by a High Court Judge, the Erebus
Commission was a Royal Commission in that the warrant was expressed to
be issued under the authority of the Letters Patent of 1917 constituting
the office of Governor-General. One of the powers delegated by the
Letters Patent to the Governor-General is to "constitute and appoint, in
Our name and on Our behalf, all such ... Commissioners ... as may be
lawfully constituted or appointed by Us". The warrant was also expressed
to be issued under the authority of and subject to the provisions of the
Commissions of Inquiry Act 1908, and s. 15 of that Act extends and
applies not only to inquiries under statutory Commissions appointed by
the Governor-General or Governor-General in Council but also to
inquiries under the Letters Patent. This means inter alia that
statutory-powers of summoning witnesses and requiring the production of
documents apply, that a Judge of the High Court acting as Commissioner
has the ordinary judicial immunity, and that interested persons have
statutory rights to be heard under s. 4A, inserted by an amendment made
in 1980 shortly before the inquiry now in question began. Section 2 of
the 1908 Act empowers the Governor-General by Order-in-Council to
appoint any person to be a Commission to inquire into and report upon
any question arising out of or concerning a range of matters. The
relevant one is "(e) Any disaster or accident (whether due to natural
causes or otherwise) in which members of the public were killed or
injured ..." In giving statutory power to appoint Commissions and
listing permissible subjects the Act differs from the Evidence Acts
considered in Australian cases. The Australian Acts presuppose the
existence of Commissions appointed under prerogative or inherent
executive powers and merely confer ancillary powers of compelling
evidence and the like. Under Acts of that type the validity of the