Deciding whether to oppose

The opposition procedure allows third parties, with the assistance of expert evidence and detailed arguments, to request the Patent Office to reconsider a decision relating to a patent or patent application. An opposition can be an effective way to prevent a particular action by the Patent Office in relation to a patent or patent application. The most common uses of the opposition procedure are to oppose a patent being granted or amended.

However, filing an opposition is not always the best offensive play. Each situation has its own unique circumstances that need to be weighed when deciding whether to commence an opposition. Depending on the circumstances, there may be other more appropriate options. Some of the typical considerations in opposing the grant of a patent are discussed below.


Advantages of an opposition

An opposition against the grant of a patent provides several advantages for an opponent, including:

  • For an opposition to the grant of a standard patent, the patent only becomes enforceable after the opposition is finally determined. This allows third parties to challenge the validity of a patent without the complication of potential infringement proceedings.
  • The opposition procedure allows for both the opponent and the applicant to file evidence of facts and expert opinion in support of their case and to make detailed submissions as to the effect of the evidence. These facts may not have been available to the examiner previously. 
  • An opposition is typically less costly than revocation proceedings. Revocation proceedings may only be brought after grant of a patent and are conducted before an Australian court. The opposition proceedings allow flexibility to run a narrow opposition on only select grounds and issues, with other issues potentially being reserved for revocation proceedings, if required.
  • The Delegates of the Commissioner of Patents charged with deciding patent oppositions have a technical background, substantially reducing the need to prepare educational evidence and submissions. The Delegates are also well versed in patent law, allowing them to quickly identify the key issues requiring determination.
  • There is very limited exposure to an award of costs against the unsuccessful party in an opposition. 
  • The opposition proceedings provide an opportunity for settlement before a patent becomes enforceable. For example, settlement may involve agreement on amendments that narrow the scope of the claims.


Key decision factors

While circumstances can widely differ, some of the typical factors to take into account in deciding whether to oppose the grant of a patent include the following:

  • What is the commercial impact of allowing the patent to proceed to grant unopposed? For example, what would be the impact of infringement proceedings against you, both financially and in relation to public or stakeholder relations?
  • What is the relationship between the patent applicant and you? Is the applicant likely to see you as a competitor, perhaps increasing the risk of adverse action, or does the applicant operate in a different area, increasing the chance of either no action being taken against you or the prospect of a favourable licence agreement?
  • What are the prospects of success in the opposition? All oppositions involve uncertainty. However, a careful analysis in advance can inform the decision of the most appropriate strategy to pursue.
  • What is the cost? Many oppositions involve substantial cost, including the cost of obtaining expert evidence. Despite this, in many cases there is however substantial flexibility in the procedure that allows costs to be reduced, with the savings balanced against the effect on the prospects of success.


Other options

There are practical alternatives to opposing the grant of a patent. These options should be considered before commencing an opposition.

Filing a notice of assertion of invalidity

Filing a notice of assertion of invalidity is an option to make the Patent Office aware of prior art relevant to a pending application. This notice may be filed on a standard patent after publication of the application and prior to its grant. On an innovation patent, such notice may only be filed after grant of the innovation patent but before its certification. Documents relevant to the novelty and inventive step/innovative step of the invention should accompany the notice.


A frequently considered alternative to lodging an opposition is to request re-examination of a patent or a patent application, for example due to newly identified prior art.

Prior to grant there is no obligation on the Patent Office to re-examine a patent application on request. In contrast, once a patent has granted, the Patent Office must conduct a re-examination of a patent on request from a third party. In some instances, re-examination of a patent application may be entered into through the opposition procedure.

The re-examination process is ex-parte: the person requesting examination files its materials, following which the Patent Office and the applicant or patentee consider the materials and decide on any required responsive action, without further input from the requestor. Generally re-examination is best suited when the patent or application is clearly invalid, rather than when there are factual and construction issues genuinely in dispute that require balancing and decision by the Commissioner.

Although it is possible for the requestor to include evidence with its request for re-examination, the costs of a party requesting re-examination are generally substantially less than the costs of an opposition. See our page on re-examination of patents for more information.

Revocation, taking a licence or acquiring the patent

Whether or not an application is opposed, there remains the option to apply to the court to invalidate a patent by revocation. It is therefore one option to do nothing and allow the patent to be granted. An application for revocation can then be made to a court at a later date. Also, a cross-claim for revocation can be made against the patent, should the patentee move to enforce the patent against you. However, if the claims of an accepted patent application would be infringed, an opposition can present a valuable mechanism to have the validity of those claims examined without the additional complication of infringement proceedings.

Other defensive actions that may be taken include searching for a ‘war chest’ of prior art for use should the patentee seek to enforce its patent, examining design around options, or investigating the option of acquiring the patent or a licence.

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