Practitioners acting for clients attacking the validity of patents and patent applications should be aware that an issue estoppel can arise in Patent revocation proceedings as a result of an earlier opposition proceeding. According to the decision of Justice O’Bryan in Orikan Group Pty Ltd v Vehicle Monitoring Systems Pty Limited (No 2) [2026] FCA 407. The outcome is the result of changes to the legal standard applied to patent oppositions brought about by the Raising the Bar Act.
Background: Orikan v VMS (No 2)
Practitioners acting for clients attacking the validity of patents and patent applications should be aware that an issue estoppel can arise in patent revocation proceedings as a result of an earlier opposition proceeding. Justice O’Bryan considered this issue in Orikan Group Pty Ltd v Vehicle Monitoring Systems Pty Limited (No 2) [2026] FCA 407. The outcome is the result of changes to the legal standard applied to patent oppositions brought about by the Raising the Bar Act.
Orikan brought proceedings for infringement of its patent against Vehicle Monitoring Systems and VMS cross claimed for invalidity relying upon the grounds of insufficiency and lack of best method. Some years earlier, VMS had opposed the grant of the corresponding accepted patent application. VMS lost that opposition and appealed the decision, with the appeal being heard by Justice Burley. Burley J handed down a judgement dismissing the appeal and rejecting the ground of insufficiency (amongst others).
Issue Estoppel and Anshun Estoppel
Justice O’Bryan held that the judicial determination of an issue of fact or of law that is legally indispensable to the determination of a ground of invalidity in an opposition proceeding under section 60(4) of the Patents Act disposes of that issue once and for all. It cannot afterwards be raised between the same parties or their privies in a subsequent revocation counter claim to an infringement proceeding or a revocation proceeding.
The court also considered whether an Anshun estoppel arose in the revocation proceeding. Referring to a separate earlier decision on this point, Justice O’Bryan noted that the reason an Anshun estoppel did not arise was because of the fundamental difference in the nature and consequences of an opposition proceeding and a revocation action. In the opposition proceeding VMS chose to initiate the action and it was appropriate to run a confined action consistent with the nature of such a proceeding. Therefore VMS could not be criticised for not raising each and every possible claim or issue in the earlier opposition proceeding.
Key Takeaways
The decision highlights the importance of carefully considering the potential impact of positions taken in opposition proceedings on subsequent litigation and whether an opponent should appeal on opposition proceedings or choose instead to pursue a revocation action in court. A question that is still unanswered is whether a decision of a hearing officer in an opposition proceeding provides a basis for asserting that an issue estoppel arises in a subsequent revocation action. Perhaps it does not given that a Patent Office decision is administrative rather than judicial in nature.
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