Patent Opposition process in Australia

Achieving “acceptance” of a patent application by IP Australia is a significant procedural milestone. It indicates that, following substantive examination, the Commissioner is satisfied that the application meets the formal requirements for grant. Acceptance, however, does not guarantee grant. Instead, it triggers a critical three-month post-acceptance opposition period, during which any third party may challenge the grant of the patent.

Opposition proceedings are a central feature of the Australian patent system. They provide a structured, adversarial mechanism for testing the validity, entitlement, and sufficiency of a patent application before exclusive rights are finally conferred. Responding effectively to an opposition requires not only technical expertise, but also a detailed understanding of statutory grounds, evidentiary rules, and procedural strategy.

Phase 1: Commencement of the Opposition Process

In Australia, opposition proceedings are governed by the Patents Act 1990 (Cth) and the Patents Regulations 1991. The opposition process is formally initiated by the filing of a Notice of Intention to Oppose. For a standard patent, this must be filed within three months of the advertisement of acceptance in the Official Journal of Patents. This notice is a relatively simple document, but it serves as the jurisdictional trigger for the proceeding. Following this, the opponent must file a Statement of Grounds and Particulars (SGP) within one month. The SGP is a foundational document that defines the scope of the opposition. It must not only list the statutory grounds, such as lack of novelty, lack of an inventive step, or non-compliance with Section 40, but also provide the “particulars”.

The particulars are the specific facts and documents upon which the opponent relies. For example, if an opponent alleges a lack of novelty, they must identify the specific prior art and indicate which claims of the patent are anticipated. If the SGP is vague or fails to provide sufficient detail to allow the applicant to respond, the Commissioner may direct the opponent to file further and better particulars. Under Regulation 5.17, the Commissioner also possesses the power to dismiss an opposition if the SGP fails to disclose a reasonable prospect of success, a measure intended to prevent vexatious or frivolous challenges.

Under Section 59 of the Patents Act 1990 (Cth), an opposition can only be based on specific, prescribed grounds. A thorough understanding of these grounds is essential for crafting a targeted defense. The most common grounds of opposition include-

• Lack of Patentability. This is a broad ground that encompasses the core requirements of novelty and inventive step. The opponent may argue that the claimed invention was already publicly available (lacked novelty) or was an obvious development to a person skilled in the relevant technical field (lacked an inventive step) at the priority date of the claims, having regard to the common general knowledge and relevant prior art. Evidence and expert opinion are central to determining whether the invention was already disclosed or would have been obvious to the skilled person.
• Non-compliance with Section 40. This ground attacks the quality and sufficiency of the patent document itself. The opponent may argue that the description is not clear and complete enough for the invention to be performed by a skilled person without undue burden. Alternatively, they may assert that the claims are not clear, succinct, and fairly based on the matter described. This means the scope of the claims might be broader than what the description actually justifies. These grounds often turn on careful technical and linguistic analysis of the specification as a whole.
• Lack of Entitlement. This is an ownership dispute. The opponent may claim that they, or someone else, is the true inventor or that the rights to the invention were not properly assigned to the Patentee as the applicant i.e., the chain of title is defective.

Phase 2: Evidentary Phase

Once the Statement of Grounds and particulars are filed, the opposition enters the crucial evidentiary phase, a structured exchange designed to allow both parties to present their case.

Opponent’s Evidence in Support

The opponent has three months to file the evidence in support to back up the claims made in their Statement. This evidence is almost invariably provided in the form of statutory declarations from technical experts, authors or inventors of cited prior arts, or witnesses to alleged prior use.

Declarations are accompanied by supporting documents and are expected to address the common general knowledge, technical context, and factual assertions relied upon.

Applicant’s Evidence in Answer

Upon receiving the opponent’s evidence, the Applicant has three months to file Evidence-in-Answer. This is the substantive core of the defense. At this stage, the applicant may:

• Rebut factual assertions
• Challenge the interpretation or relevance of prior art
• Provide expert evidence explaining why the invention is novel and inventive
• Address entitlement or sufficiency challenges

Evidence in Answer is typically supported by independent expert declarations, which must be carefully structured to assist the Hearing Officer in understanding the technical field, the problem addressed by the invention, and why the opponent’s case is unsound.

Opponent’s Evidence in Reply

The opponent then has a final opportunity to file Evidence-in-Reply, typically within two months. Critically, this evidence must be strictly in reply to the matters raised in the Evidence-in-Answer. The Opponent cannot use this stage to introduce new grounds of opposition or repair gaps or deficiencies in their initial evidence.

The outcome of a patent opposition is almost always determined by the strength and persuasiveness of the evidence filed. Assertions unsupported by admissible evidence carry little weight.

Evidence must be presented in a specific format, typically as a statutory declaration, i.e., a written statement of facts that the declarant formally and sincerely declares to be true. The preparation of this evidence, particularly expert evidence, is a nuanced art. Statutory declaration must be factually precise; avoid advocacy masquerading as evidence; and clearly distinguish between factual assertions and expert opinion.

An expert declaration must do more than simply offer a conflicting opinion to the opponent’s expert. It must be a carefully constructed narrative that educates the Hearing Officer on the technical field, the common general knowledge at the time, the problems the invention solved, and why the invention was not obvious.

That said, navigating the evidentiary periods requires diligent project management and strategic foresight. While extensions of time were once common, recent changes to Australian patent regulations have made them significantly harder to obtain.

A party seeking an extension must now satisfy the Commissioner of Patents that they have made all reasonable efforts to comply with the deadline and have acted promptly and diligently at all times, or that exceptional circumstances exist.

Routine workload pressures or strategic delay are no longer sufficient. This heightened standard makes disciplined project management and early evidence preparation essential.

Phase 3: The Hearing and Decision

After all evidence is filed, the opposition proceeds to a hearing before a delegate of the Commissioner of Patents. Hearings may be conducted on the papers, but oral hearings are commonly requested where issues are technically or legally complex.

Following the hearing, the delegate will issue a reasoned written decision. The decision may be that the opposition is dismissed and the application is allowed to proceed to grant; that the opposition is successful and the application is refused; or allow the application to proceed subject to acceptable amendments to overcome the grounds of opposition. Throughout the opposition, commercial settlement remains possible, including coexistence agreements or licensing arrangements. An adverse decision may be appealed to the Federal Court of Australia, where the matter is heard afresh.

Costs and the Right of Appeal

The Commissioner has the authority to award costs against the unsuccessful party. These costs are not intended to fully indemnify the successful party for their legal fees; rather, they are calculated according to a schedule set out in the Regulations (Schedule 8). These awards are relatively modest compared to the actual costs of patent litigation, reinforcing the opposition process’s role as a more accessible forum.

As stated, the decision of the delegate of the Commissioner of Patents is not final. Under the Patents Act, either party may appeal the decision to the Federal Court of Australia. An appeal is a “hearing de novo”, meaning the Court can hear the entire matter afresh, including new evidence and new arguments. This provides a judicial safeguard to the administrative process, ensuring that the final determination of patent rights is subject to the scrutiny of the court system if necessary.

Strategic Claim Amendments

Often, the most effective path to resolving an opposition is through strategic amendment of the patent claims. This is not an admission of weakness but a pragmatic and powerful tactic to overcome the opponent’s objections while preserving commercially significant protection. Narrowing claims to distinguish cited prior art is not a concession of invalidity, but a recognized and often commercially sensible mechanism to secure grant.

However, proposing amendments during an opposition is a formal process with its own set of rules. Any post-acceptance amendment must not result in the claims covering subject matter that was not in substance disclosed in the original application. Furthermore, the proposed amendments are advertised, and the opponent has an opportunity to comment on them or, in some cases, formally oppose them under Section 104 of the Patents Act 1990 (Cth). This can lead to “procedural opposition” within the main substantive opposition, adding an additional layer of complexity.

Procedural Oppositions

The Australian patent system also provides for oppositions against certain procedural actions, which can be equally critical to the patent rights. These include-

• Opposition to Extensions of Time- Obtaining an extension of time under Section 223 of the Patents Act 1990 (Cth) requires meeting a high threshold. If an opponent believes that the Patentee has not taken due care or that there are no exceptional circumstances, they can oppose the request for extension of time. Defending this requires detailed evidence of the circumstances that led to the delay.
• Opposition to the Grant of a License- In certain circumstances, a third party can apply for a compulsory license to exploit a patented invention. The grant of such a license can be opposed and defending this involves complex arguments around reasonable requirements of the public and the patentee’s commercial activities.

While less common than substantive oppositions, these procedural challenges require the same level of strategic attention and expert representation to ensure patent rights are fully protected throughout the patent lifecycle.

Conclusion

Australian patent oppositions are evidence-driven and strategically significant. A successful response or opposition strategy requires disciplined management of statutory deadlines, careful construction of expert evidence, and a clear understanding of how legal standards are applied by IP Australia delegates.

If you are facing an opposition to your Australian patent application or are looking to oppose an application, specialist legal advice should be sought promptly.

With our deep expertise in Australian patent law and opposition practice, we provide the strategic counsel and powerful advocacy needed to navigate this complex landscape. We partner with you at every step, transforming a potential threat into an opportunity to secure a valid and commercially powerful patent.

Contact us today for a free consultation.