In South African administrative law, the issue of invalid administrative action in relation to the application of the doctrine of functus officio has brooked a fair amount of debate. Whilst the courts have attempted to articulate an appropriate approach to be adopted regarding the variation or revocation of invalid administrative action, the issue remains one that is often fraught with a degree of uncertainty. A decision once made by an administrator, which is final, cannot be revisited in the absence of statutory authority. The invalidity of an administrative act does not detract from the legal consequences thereof which are binding until varied or set aside by a court of law. This tension between legality and finality is compounded when considering issues of fairness and administrative efficiency. It has been suggested that it is the task of the legislature to resolve this tension. This paper argues that despite the degree of uncertainty, the courts have in fact adopted a more flexible approach regarding the functus officio doctrine with reference to relevant constitutional and legislative imperatives. As such, there is no need for the legislature to resolve the tension. In so doing, the courts have effectively given effect to the essence of administrative justice.

Keywords: functus officio; invalid administrative action; legality; certainty; administrative efficiency