The first plaintiff, as patentee, applied under ss 39 and 40 Patents Act to amend his New Zealand patent. This was opposed by the defendants. The patent related to devices designed to cut and pulverize materials by using jaw attachments for excavators.

The first plaintiff was also proprietor of a corresponding Australian patent that had been re-examined, a process that brought to the first plaintiff’s attention prior art that might have been available in New Zealand before the priority date of the New Zealand patent. As a precaution the first plaintiff applied to amend the New Zealand patent on 21 December 2006.

It was common ground that the Court had jurisdiction under s39 to make the orders sought and that the proposed amendments were in proper form under s40, being disclaimers and a correction. At issue was whether this was an appropriate case for the Court to allow the amendments in the exercise of its discretion. 

The application to amend was made in the context of existing litigation by the first plaintiff alleging infringement of the patent against the defendants and a further party.

The corresponding Australian patent had been re-examined in 2005. Leave to amend was granted by IP Australia on 19 May 2006. Subsequently opposition was filed to the Australian amendment. After further amendments proposed by the applicant, leave to amend was finally granted by IP Australia on 15 August 2008 with the amendments being advertised in February 2009.

The defendants opposed the granting of leave to amend on the basis that:

(a)   The application should be treated as one of rewriting and the law on deleting amendments disregarded in this case;

(b)   There was considerable delay when re-examination of the corresponding Australian patent was being conducted and yet at the same time the plaintiffs (through their New Zealand counsel) were vigorously promoting the infringement litigation in New Zealand;

(c)   The delay should be counted from when the patentee or his agent knew or ought reasonably to have appreciated that the prior art caused a problem and that a patentee should move as soon as is reasonably practical;

(d)   There had not been candid disclosure of all material facts nor had the patentee adequately explained the delay.

Stevens J allowed the amendments. The key findings of the judgment were:

(i)   The amendments were deletions and complied with s40.  

(ii)   The first plaintiff had been entirely frank and open about the circumstances relevant to the application. He had modest financial resources and it was entirely understandable that he was hoping to have the Australian amendment considered and approved by the Australian examiner and to use this as a basis for amendment in other jurisdictions, including New Zealand.

(iii)   Prior to October 2006, there was no knowledge of circumstances by the first plaintiff or his agent that would have warranted an application to amend. Following counsel being instructed, the applicant acted entirely reasonably and properly.

(iv)   As to covetousness, the first plaintiff was not deliberately trying to maintain a monopoly in respect of the New Zealand patent to which he knew he was not entitled. Further, this was not a case where the patentee had knowingly and deliberately sought to make patent claims of unjustifiable width. Once it became clear that the Australian re-examination process was likely to become problematic after September 2006, the first plaintiff took prompt and reasonable steps to obtain advice in New Zealand regarding the desirability of applying to amend the New Zealand patent. Covetousness requires the formation by a competent professional of a view that the patent is invalid, coupled with a deliberate decision to hide that fact and/or a failure to act.

(v)   There was no delay here of the type that would warrant the court exercising a discretion to decline the amendment. No public interest was affected and the defendants has not shown on the evidence any specific prejudice.