Unreasonableness is Available as a Ground for Judicial Review!
Two Federal Court decisions have suggested that the ground of unreasonableness is not available as a ground of judicial review in migration law as far as the doctrine of jurisdictional error is concerned.
But transcripts of two High Court special leave hearings reveal that the High Court believes there is no question that unreasonableness is a ground of judicial review.
The first Federal Court case is Andary v MIMA  FCAFC 211 (28.8.03) where the Full Court in a joint judgement said:
19 The decision is largely based upon the Minister’s view of the seriousness of the appellant’s criminal record and his perception of the expectations of the Australian people. The exposure of these grounds for the decision makes it very difficult to apply the concept of Wednesbury unreasonableness to the case, with or without the assistance of the notion of proportionality. Views of the seriousness of a particular criminal record will vary greatly from person to person, as will opinions as to the expectations of the Australian community. In this case, the question is whether any of the bases for challenge identified in Hickman has been established. Although the decision may be harsh, we are unpersuaded that any such basis can be demonstrated.
20 This conclusion makes it unnecessary for us to consider the quite important question of whether a decision which is unreasonable in the Wednesbury sense involves jurisdictional error. In MIMA v Eshetu  HCA 21; (1999) 197 CLR 611, Gleeson CJ and McHugh J said at :
`The proposition that the Tribunal’s decision manifested “Wednesbury unreasonableness” has not been sustained. Even if it had been sustained, Hill J was right to conclude that it did not provide a ground upon which the Federal Court could set aside the Tribunal’s decision.’
The applicant failed before the Full Federal Court and failed to obtain special leave to the High Court. Oversimplifying the facts, the visa holder had his visa cancelled on character grounds because of serious drug convictions. All courts that looked at the matter did not conclude the decision was unreasonable even though the visa holder had been in Australia since as a child.
But in the transcript before the High Court Gummow J said:
GUMMOW J: There are, I think, now sufficient decisions to indicate Wednesbury unreasonableness, to use that term, can give rise to jurisdictional error for the purposes of s. 75(v) of the Constitution, and, therefore, for the construction of s. 474 [of the Migration Act], but your burden is to show that that being the accepted law, either you want to reformulate it in some way; and two, whether in any event, even if reformulated, this would be a case in which you have sufficient prospects of success of winning even on a reformulated, widened basis of Wednesbury unreasonableness.
In Auro v MIMA  FCA 1857 (28.11.07) Collier J said:
30 Fourth, I agree with the submission of Mr Bickford that it is yet to be established whether a decision which is unreasonable, in the sense explained in the Wednesbury case, is amenable to review for jurisdictional error in Australia: Andary v Minister for Immigration & Multicultural Affairs  FCAFC 211 at . (I note further with respect to this point that the High Court refused leave to appeal from the decision in Andary  FCAFC 211: Andary v MIMA.
Again the applicant was unsuccessful in both an appeal to the Federal Court and in applying for special leave to the High Court, but not because unreasonableness was NOT available (see Auro v MIMA  HCATrans 248).
Here is an exchange with counsel on this point:
Counsel: I submit the difficulty with that is just caused by the hiatus about the unreasonableness issue. If I take you to page 28 of the record and the difficulty will be that if your Honours do not grant special leave, obviously submissions would be made around Australia that there are now two cases where the High Court has refused special leave on the unreasonableness point.
GUMMOW ACJ: We have said on various occasions, various judges have said, that Wednesbury unreasonableness could give rise to jurisdictional error.
So there it is, straight from High Court transcripts – unreasonableness is available to prove jurisdictional error! Special leave transcripts are not precedents in a strict sense but it would be a powerful tool in advocacy to show that unreasonableness is available in judicial review in migration matters.
 Andary v MIMA  HCATrans 242 (23 June 2004)