Australia patents update: Federal Court revisits best method knowledge requirement for divisional patents

The Federal Court’s decision in The NOCO Company v Brown and Watson International Pty Ltd [2025] FCA 887 has provided a welcome update on the relevant date for assessing the best method knowledge requirement for divisional patents. Justice Moshinsky concluded that for divisional patents, the best method requirement is assessed by reference to the applicant's knowledge when the earliest related complete application (including a PCT application) was filed, not when the divisional application itself was filed.

The patents in dispute in the NOCO case

This case involved a dispute between The NOCO Company (NOCO) and Brown and Watson International Pty Ltd (B&W) concerning three Australian patents owned by NOCO for a portable vehicle battery jump starter apparatus with safety protection. NOCO alleged that B&W’s products infringed its patents, and B&W cross-claimed for revocation, alleging that the asserted claims of the patents were invalid on multiple grounds, including failure to disclose the best method.

The Federal Court of Australia, constituted by Justice Moshinsky, found that all the asserted claims of the patents were invalid on the ground that they each lacked an inventive step. However, his Honour also carefully considered other issues alleged by B&W, including lack of novelty, failure to disclose best method, and non-infringement arguments. In this article, we discuss the Court's analysis of the best method ground.

Best method requirement and the relevant date

Section 40(2)(aa) of the Patents Act 1990 (Cth) requires that a complete specification “disclose the best method known to the applicant of performing the invention”. Australia is one of the few jurisdictions retaining this “best method” (or best mode) requirement. In recent years, patent challengers have often been attracted to this requirement as a ground of asserted invalidity

A key issue in NOCO was the relevant date for assessing the applicant's knowledge as to the best method. On the facts, the options were:

• The filing date the PCT application (2014) (NOCO’s position); or

• The filing date of each of the divisional patent applications (2020-2022) (B&W’s position).

If the relevant date had been the filing date of each divisional patent application as B&W contented, then NOCO would have failed to disclose the best method known at those later dates, due to better methods having been learned between 2014 and 2020-2022.

Justice Moshinsky held that NOCO’s position was to be preferred, finding that the relevant date for assessing the best method “knowledge element” was the filing date of the earliest complete specification in the family – the date on which the standard 20-year monopoly commences for all patents within that family, including all divisional patents.

Departure from a problematic precedent: Dometic Australia

Justice Moshinsky's finding stands in contrast to an earlier, and controversial, decision Dometic Australia Pty Ltd v Houghton Leisure Products Pty Ltd [2018] FCA 1573 (Dometic), in which Justice White found as part of the ratio of that case that the relevant date for a divisional patent was the filing date of the divisional application itself. There was no appeal from Dometic, and its findings have been the law of the land on this issue, at least until this new decision in NOCO.

The Dometic decision had created difficulties for patent applicants/patentees of divisional patents, whose knowledge in the relevant field of technology by the date of filing the divisional application often included newer and better methods not known to the applicant at the time of filing (and therefore not disclosed in) the earliest related complete application in the patent family.

The ruling in Dometic was particularly problematic for owners of post-Raising the Bar patents (ie., patents for which examination was requested after 15 April 2013). For post-Raising the Bar patents, it is not possible to add matter to a complete specification by way of amendment, so there was a risk of failure to disclose the best method under the Dometic line of authority, which was potentially incurable by amendment.

Reasoning in NOCO

Justice Moshinsky considered it was not necessary to form a view as to whether the holding in Dometic was “plainly wrong” (as NOCO submitted it was). However, his Honour’s reasoning appears implicitly to accept that it was.

In reaching his views, Justice Moshinsky relied on authorities that predated Dometic, including:

• Rescare Ltd v Anaesthetic Supplies Pty Ltd (1992) 25 IPR 119, where Justice Gummow opined that the relevant date for assessing the applicant's knowledge for the best method requirement, for an Australian national phase entry of a PCT application, is the international filing date.

• Pfizer Overseas Pharmaceuticals v Eli Lilly & Co [2005] FCAFC 224, in which the Full Court confirmed that the requirement is for the complete specification, as it exists when it is being assessed by the Commissioner/Court, must disclose the best method that was known to the applicant as at the filing date.

• Mont Adventure Equipment Pty Ltd v Phoenix Leisure Group Pty Ltd [2009] FCAFC 84, in which the Full Court construed the phrase “the filing date of the complete application” for a divisional application as being the filing date of the parent application.

Justice Moshinsky concluded that there was no good reason why the knowledge element for divisional applications should not be assessed as at the filing date of the ultimate parent application.