For decades, following the grant of a patent, a competitor or other third party seeking to challenge the validity of the patent had only one recourse: commencing invalidation proceedings before the High Court. This meant navigating the time, expense and procedural burdens associated with full-scale civil litigation.
 
That has now changed. On 31 December 2025, Malaysia brought into operation its post-grant patent opposition regime under the Patents Act 1983¹ (“PA 1983”), introduced by the Patents (Amendment) Act 2022² (“PAA 2022”) and implemented through the Patents (Amendment) Regulations 2025 (“2025 Regulations”) and MYIPO's Practice Notice No. 1/2025. For the first time, Malaysia has an administrative mechanism before the Registrar of Patents (“Registrar”), providing an alternative pathway for challenging a granted patent through a structured opposition process.
 
Why Opposition and Why Now?
 
The rationale is straightforward: patent examination, however rigorous, is not infallible. Relevant prior art may emerge, claim scope may give rise to concerns, or issues relating to patentability and disclosure may only become apparent after grant. Post-grant opposition provides a structured, time-limited mechanism for third parties to raise these concerns before the Registrar, offering an early administrative review before a patent becomes entrenched in commercial practice. The introduction of this regime also aligns Malaysia more closely with established patent systems, including the European Patent Office, which has long maintained an administrative opposition procedure.
 
Who Is Entitled to Oppose
 
Unlike the patent opposition system under the European Patent Convention, which permits “any person” to oppose a granted patent, Malaysia requires an opponent to qualify as an “interested person”.³
 
The term “interested person” is not defined in the PA 1983 or the 2025 Regulations except for an explanation that it includes the Federal Government and a State Government⁴. Its scope will likely develop through MYIPO practice and ultimately judicial interpretation.
 
An interested person who is not resident in Malaysia is required to furnish security for costs as determined by the Registrar at the time of filing the notice of opposition.⁵ This requirement ensures that any costs awarded against a non-resident person in the opposition proceedings will be secured.
 
Grounds of Opposition
 
Opposition under this new regime is not an open-ended challenge to a granted patent. The grounds of opposition are confined to the statutory grounds set out in the PA 1983.⁶ The principal grounds include:
 
i. Non-patentability
 
The claimed subject matter fails to satisfy the patentability requirements under the PA 1983, in that it does not satisfy the meanings of an “invention”⁷ and “patentable inventions”⁸, the requirements of novelty⁹, inventive step¹⁰ and industrial applicability¹¹.
 
ii. Excluded subject matters
 
The inventions which are non-patentable¹² include:

Performance of any act in respect of the claimed invention that is contrary to public order or morality¹³ will also be excluded.
 
iii. Non-compliant Specifications
 
The patent specification does not comply with the requirements of the PA 1983¹⁴, for example where the description is insufficient¹⁵, the claims lack clarity or support¹⁶ or required drawings¹⁷ or other necessary requirements/ information have not been provided or complied with¹⁸.
 
These grounds reflect the principle that post-grant opposition is intended to provide a focused review of patent validity issues, rather than a general reconsideration of every possible dispute concerning a granted patent.
 
Unlike invalidation proceedings before the High Court, the post-grant opposition regime does not appear to provide a mechanism for resolving entitlement or ownership disputes. Such disputes would need to be addressed through other available proceedings.
 
Deadline and Procedures

i.  Filing the Opposition 
 

To oppose the grant of a patent, an interested person must file a Notice of Opposition (“NOO”) within six months from the date of publication of the grant in the Intellectual Property Official Journal (Patent).¹⁹ No extension of time is permitted for this deadline.  The NOO must set out the grounds of opposition, including the facts relied upon by the interested person and the relief sought, and supported by evidence in the form of a statutory declaration.²⁰ Additional grounds of opposition may also be filed subsequently, provided they are submitted within the same six-month opposition period.²¹

ii.  Notification to the Patent Owner 
 

Once the NOO satisfies the prescribed formality requirements, the Registrar will issue a copy of the NOO, and the additional ground of opposition, if any, to the patent owner.²²

iii.  Filing the Counterstatement 
 

The patent owner then has three months from the issuance of a copy of the NOO by the Registrar to file a Counterstatement.²³ The Counterstatement shall be accompanied by a statement to support the grant of the patent and to object to the ground of opposition. Evidence in support of the statement by way of a statutory declaration should also be filed together.²⁴
 
At the same time, or subsequently, the patent owner may seek to amend the granted specification in response to the opposition.²⁵ However, if no Counterstatement is filed within the prescribed period, the patent owner will be precluded from proceeding further in the opposition proceedings.²⁶

iv. Evidence in Reply and Written Submissions 
 

The opponent is next given three months to file Evidence in Reply, including any response to the proposed amendment.²⁷ The Registrar may notify the parties to file Written Submissions within three months from the date of issuance of the notification.²⁸
 
The timelines governing the opposition process are generally strict. A maximum extension of one month may be granted, but only once and only in respect of the filing of the Counterstatement, a request to amend the patent, Evidence in Reply, or Written Submissions.²⁹ As mentioned earlier, no extension is permitted for the filing of the NOO.

v.  Ad Hoc Opposition Committee

 
A distinctive feature of Malaysia’s new opposition regime is the establishment of an Opposition Committee. The Registrar may convene an ad hoc Opposition Committee to provide its recommendation.³⁰ The Committee’s role is substantive rather than merely procedural, as its assessment assists the Registrar to make a decision on the opposition.
 
vi.  Decisions
 
At the conclusion of the opposition proceedings, the Registrar may maintain the patent as granted, maintain the patent with amendments, or invalidate the patent.³¹
 
If the Opposition Committee recommends the patent to be invalidated³², the process does not necessarily end there. The Registrar may give the patent owner an opportunity to make a request to amend his patent.³³ This additional stage reflects a deliberate policy choice to provide patent owners with an opportunity to preserve valid claim scope through amendment, rather than resulting in outright revocation where narrower protection may remain justified.
 
Where the Registrar decides to invalidate, any amendment proposed by the patent owner cannot disclose matter going beyond what was originally disclosed, it cannot extend the scope of protection conferred at grant and must be made within the scope specified in the Registrar’s notification.³⁴
 
vii.  Appeal
 
A party dissatisfied with the Registrar’s final decision may appeal to the High Court within one month from the date of the Registrar’s decision.³⁵ The availability of an appeal provides judicial oversight of the administrative process while maintaining the efficiency intended by the opposition framework.
 
Where a patent is maintained following opposition, the same opponent is precluded from subsequently commencing invalidation proceedings on the same grounds, except where the challenge is raised by way of a counterclaim in infringement proceedings or on appeal.³⁶ This provision gives the opposition process a degree of finality between the parties and prevents an unsuccessful opponent from repeatedly challenging the same patent on identical grounds.
 
However, parties involved in subsequent infringement proceedings may still challenge the validity of the patent on the grounds available under the PA 1983.³⁷ regardless of the outcome of the opposition proceeding.³⁸ Accordingly, post-grant opposition should be viewed as an early administrative review mechanism rather than a final determination of patent validity.
 
A Practical View
 
The introduction of Malaysia’s post-grant opposition regime creates a new strategic checkpoint following the grant of a patent. Previously, a challenger seeking to question the validity of a granted patent would generally have had to consider the cost, time and complexity of commencing High Court invalidation proceedings. Parties now have an intermediate administrative route before MYIPO to assess the validity of a granted patent at an earlier stage.

i.  Patent Owners: Managing Post-Grant Validity Risk 
 

Under the previous framework, once a patent was granted, a patentee could generally expect that any validity challenge would require a challenger to undertake the significant time, cost and procedural commitments associated with court proceedings. The introduction of the post-grant opposition regime changes this dynamic by providing a more accessible administrative route for early validity challenges.
 
The first six months following publication of the grant should therefore be regarded as a critical monitoring period for patent owners. During this period, patent owners should actively monitor the Intellectual Property Official Journal for newly granted patents, assess the likelihood of challenges from competitors, and prepare technical and legal positions promptly. It is also important to preserve relevant prosecution records, experimental data, inventor declarations and other supporting materials that may become necessary to defend the validity of the patent.
 
As no extension of time is available for filing a notice of opposition, patent owners should consider undertaking post-grant preparation rather than wait until an opposition is filed. For commercially significant patents, a post-grant vulnerability review may be valuable, particularly focusing on potential novelty-destroying prior art, inventive step weaknesses, claim clarity and support issues, disclosure sufficiency, and any claim amendments made during prosecution that may attract scrutiny.
 
A patent that has successfully navigated examination may nevertheless face a focused challenge from a competitor with access to industry-specific prior art or technical information that was not previously available to the examiner.

ii.  Potential Opponents: Opposition as a Pre-Litigation Strategy 
 

For challengers, the new regime provides an additional strategic option before committing to a full scale invalidation proceedings. A potential opponent may consider filing an opposition where a competitor’s newly granted patent raises freedom-to-operate concerns, the patent creates commercial uncertainty, or court proceedings would be premature or disproportionate at that stage.
 
However, opposition should not be viewed merely as a lower-cost substitute for invalidation proceedings. The challenger must act within the strict six-month opposition period and develop its case promptly, including identifying relevant prior art, assessing claim scope, and obtaining the necessary technical evidence to support the grounds of opposition.
 
The most effective oppositions are likely to be those supported by focused prior art searches, detailed claim charts mapping the cited prior art against the patent claims, appropriate technical evidence, and a clear explanation of why the patent fails to satisfy the statutory requirements. Conversely, a poorly prepared opposition may provide the patent owner with an opportunity to refine its position and potentially strengthen the patent through amendments.
 
From a commercial perspective, potential challengers should therefore treat opposition as a strategic decision rather than simply a procedural step. The objective should be to determine whether early administrative intervention can achieve a meaningful commercial outcome, whether by removing problematic patent rights, narrowing claim scope, or improving the challenger’s freedom to operate.

iii.  Opposition May Become a Tool in Commercial Negotiations 
 

The availability of post-grant opposition may influence the dynamics between patent owners and competitors in commercial negotiations. Previously, a patent owner facing a potential validity challenge could generally expect a challenger to incur the significant costs and commitments associated with court proceedings before testing the strength of the patent. The new opposition regime allows such challenges to be raised earlier, and potentially affect the balance of leverage between the parties.
 
In practice, the availability of opposition may encourage earlier engagement on licensing discussions, influence settlement strategies, and increase the willingness of parties to consider claim amendments or other commercial arrangements. It may also prompt more frequent pre-enforcement patent reviews, particularly before a patent owner takes steps to assert newly granted rights against competitors.
 
Patent owners should therefore consider the potential opposition risk when developing enforcement strategies after grant. An aggressive enforcement approach, particularly in commercially competitive fields, may prompt competitors to use the opposition window as an early mechanism to challenge the patent’s scope or validity.

iv.  Timing as a Strategic Consideration 
 

This compressed timeframe makes early detection of competitor patent grants particularly important. A competitor who discovers a problematic patent after the expiry of the six-month period will lose access to this administrative route and may need to rely on later invalidation proceedings or raise invalidity arguments during infringement litigation.
 
Accordingly, companies operating in patent-sensitive industries should consider implementing patent watch services, competitor patent monitoring and internal escalation procedures after patent grant publications. This is particularly relevant for industries with dense patent portfolios, such as pharmaceuticals, biotechnology, electronics, telecommunications, and manufacturing.
 

v.  The Development of Malaysia Opposition Practice 
 

As Malaysia’s first administrative post-grant opposition system, the practical operation of the regime will inevitably develop over time. Several issues remain to be clarified, including the scope of the term “interested person”, the evidential standards applied by the Opposition Committee and the Registrar, the approach to claim amendments during opposition, and whether Malaysian practice will draw guidance from established opposition systems, such as that of the European Patent Office.
 
Conclusion
 
Malaysia’s post-grant opposition regime represents a significant shift in patent strategy. Patent grant is no longer the final milestone before enforcement; it now marks the beginning of a potential administrative review period during which the validity and scope of protection may be tested. Patent owners will need to adopt a more proactive post-grant monitoring and risk management approach, while competitors must evaluate newly granted patents promptly and strategically within the limited opposition window. As the first decisions emerge, they will provide valuable guidance on whether post-grant opposition becomes a regular strategic tool in Malaysian patent practice or remains an exceptional mechanism reserved for significant patent disputes.
 
 
Article by Teh Hong Koon (Partner) of the Intellectual Property Practice of Skrine.
 

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