Mishka Hudson Hi Michael, the following may be of interest to you;

The High Court of Australia has affirmed the vitality of traditional equitable doctrines, as supported by Muschinski v Dodds [1985] HCA 78, 160 CLR 583. http://www6.austlii.edu.au/.../au/cases/cth/HCA/1985/78.html

To see this upheld in practice you can review;

The High Court position, held in Australia Taylor v. Taylor (1979), as follows;

“…So far as material to this case s. 79A (1) of the Family Law Act 1975 (Cth) provides that "When, on application by a person affected by an order made by a court under section 79, the court is satisfied that the order was obtained by fraud, by duress, by the giving of false evidence or by the suppression of evidence, the court may, in its discretion, set aside the order . . .". Section 83 provides, inter alia, that "in proceedings with respect to the maintenance of a party to a marriage . . . if there is in force an order with respect to the maintenance of that party . . . the Court may . . . (c) discharge the order. . . ."