Abstract
The opposition procedure in Australian patent law permits third parties to challenge the validity or scope of a patent application before the patent is granted. There have been suggestions, in the interests of harmonisation with other jurisdictions that the system should change so that the challenge is available after the grant of the patent. This article explores the purposes of the opposition procedure through a consideration of it in terms of the patent examination procedure, actions for revocation of patents and the principles that underpin the system as a whole. It is after a more complete understanding is achieved that attention is paid to three areas of potential reform - limiting the opposition procedure to an ex parte one (in order to reduce delays); removing the responsibility from the Patent Office; and the possibility of instituting a post-grant opposition procedure.