Last updated: 
3 April 2014

A patent opposition process allows a person to challenge the validity of an innovation patent, or an application for a standard patent before it is granted.

Patent oppositions can be made against:

  • an accepted standard patent application
  • a certified innovation patent.

Other actions under the patent legislation can also be opposed including:

  • an applicant's or patentee's request for leave to amend their patent specification 
  • an applicant's grant of an extension of time to restore a patent or patent application 
  •  patentee's grant of an extension of term of a pharmaceutical patent
  • the grant of a licence to use an invention.

Reasons for opposing the grant of a standard patent

The most common reason for opposing the grant of a standard patent is that the invention claimed in the application is not new and/or inventive. Other reasons may also be given, including that the patent applicant is not the owner of the invention.

When to file a patent opposition

If you want to oppose a patent or patent application you must file a notice of opposition with us. Given the cost and complexity of these proceedings, it is advisable to obtain appropriate professional advice before you file a notice of opposition.

The notice of opposition to the grant of a standard patent application must be filed within 3 months of when we publish a notice that the application has been accepted.

An innovation patent may be opposed any time after we certify the innovation patent.

The time frames for opposing other actions vary under the Patents Act 1990.

The cost of opposing a patent

There are fees for filing the notice of opposition, for appearing at the hearing and for an extension of time if requested.

The most significant costs will be for getting legal advice, engaging a legal representative (if you decide you need one) and for the preparation of evidence. Costs for the preparation of evidence will include the expense of engaging relevant technical experts.

While the winning party is generally entitled to an award of its costs, this award is normally limited by the legislation and usually amounts to a small proportion of the actual costs that the winning party would have accumulated during the opposition process. Even if you win, you will usually not recover your actual costs and if you lose, you may also be liable for the other party's costs.

What you will have to prove

When an opposition is filed, the patent applicant or patentee and the opponent each have an opportunity to give evidence to the Commissioner of Patents.

As an opponent, you'll need to prove a lack of newness or inventive/innovative step in light of information that may or may not have been considered when the application or patent was examined, or use other grounds to argue that the application or patent is invalid.