Double patenting is the granting of two patents for a single invention to the same Applicant in a single country. Double patenting is not allowed because two patents for the same invention cannot be granted to the same Applicant. This article goes through the differences between double patent in Australia and New Zealand in relation to standard patent applications.
Double patenting in Australia is prohibited under section 64(2) of the Patents Act 1990 (Cth) for standard patent applications. This section specifies that a patent application cannot be granted if it ‘claims an invention that is the same as an invention that is the subject of a patent and is made by the same inventor’.
The test for determining whether the claims define the same invention is ‘if the claims of the two specifications were located in the same specification, would there be redundancy of claiming?’ (Smithkline Beecham p.l.c  APO 54). As such, in Australia, for double patenting to be applicable, the overall scope of the claims must be identical. In this regard, overlapping claim scope between a parent patent and a divisional patent application is allowable as long as the overall scope of the two are not identical.
In Australia, a double patenting objection can be addressed by withdrawing one of the applications or by simply amending the claims. In this regard, by withdrawing the patent (such as a certified innovation patent), the application no longer has overlapping claim scope with the subject of another patent and can proceed towards grant.
In Australia, it is allowable for an Applicant to obtain a patent for an invention and pursue broader protection in a divisional patent application. However, New Zealand is a different matter.
Double patenting in New Zealand is prohibited under regulation 82 of the Patents Regulations 2014. This regulation specifies that an application which includes claims for substantially the same matter as that already accepted for a divisional or parent application (of the same Applicant) cannot be accepted. As such, the claims of a divisional or parent application must not include claim(s) for substantially the same matter as that of an accepted divisional or parent application.
Presently, New Zealand Examiners appear to be raising a double patenting objection when there is overlap (any overlap) between the claims of a parent and the claims of a divisional application. Unlike Australia, it appears that a double patenting objection in New Zealand cannot be addressed by withdrawing the accepted or granted parent because the wording of regulation 82 indicates that the status of the patent or patent application is irrelevant.
Unfortunately, it appears that it is impermissible to obtain a patent for an invention and pursue broader protection in a divisional patent application because this would result in overlap in claim scope and thus a double patenting issue.
Whilst double patenting is relatively easily addressed in Australia, it is a different story in New Zealand.
In Australia, a double patent objection can be avoided by ensuring that the claims of a parent and divisional patent application are not identical. Alternatively, if the claims are identical then the granted patent can be withdrawn to allow the other application to proceed towards grant.
In New Zealand, we recommend more consideration be given to the divisional filing strategy. Whilst there are a number of strategies that can be utilized to address double patenting in New Zealand, it would be wise to consider these prior to the parent application being accepted.
Patents and patent applications directed to chemical compounds can cover an extremely large scope of compounds and so double patenting can be a significant issue. As such, when filing a divisional patent application directed to chemical compounds, we recommend additional consideration be given to the divisional filing strategy.
Please do not hesitate to contact us if you have any questions or queries, or if you require any further information regarding double patenting in either Australia or New Zealand.