Patents of Addition: A Strategy to Protect Improvements or Modifications in an Invention in Australia and New Zealand


With Australia’s second tier innovation patent system set to be phased out, as we have reported previously, this will remove an option for protecting improvements in Australia with a lower level of ‘inventiveness’ (when compared with the prior art) than is required for a standard patent.

However, in the case of a modification of, or improvement in an applicant’s own invention which falls below the inventive step threshold with regard to the earlier invention, both Australia and New Zealand allow for patents of addition which may be suitable for protecting the modification or improvement.

Patents of addition are similar to US continuation-in-part applications and may be suitable for a modification of, or improvement in the invention of a ‘parent’ Australian or New Zealand application or patent, provided that the variation has not been described in a patent specification or made available to the public previously.

There have been few legal decisions in Australia or New Zealand related to patents of addition. English courts have defined a modification as ‘an alteration which does not involve a radical transformation’,[1] whereas an improvement has been defined as ‘a variation, whether by addition, omission or alteration, to secure a better performance, whilst retaining some characteristic part’.[2]

Whereas the scope of “modification” or “improvement” is not entirely clear, it is reasonable to assume that if the claims of the new application are obvious in view of the original application, then it would come within the scope of “modification” or “improvement” and hence a patent of addition would be appropriate. If, on the other hand, the new claims are inventive over the original application, it may not be regarded as a “modification” or “improvement”, but would then be a reasonable invention for a stand-alone application.

The publication of, or use of the invention described in the parent is excluded when assessing the inventiveness, but not novelty, of a patent of addition. A patent of addition can only be granted after grant of the parent, and is only in force while the parent is in force, although it can be converted to a standard patent (e.g. if the parent is revoked).

The term of a patent of addition does not extend beyond the term of the parent. Further, no renewal fees are payable for a patent of addition after grant.

Please contact us for further information regarding patents of addition, or any other forms of intellectual property protection.

[1] Elliott Brothers (London) Ltd’s Application [1967] RPC 1, 4-5.

[2] Ibid.

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