Possible texts to deal with this issue may include the following options:
Third Parties Opposition
1. Any interested person shall have the right to file observations on an application, within ... days from the publication of the application, if such person deems that the invention does not meet any of the patentability requirements or that the application does not comply with other provisions of the law. In examining the application, the Patent Office shall take into consideration the reasons alleged by the third party.
2. After the granting of a patent, any interested person may apply for an order before the Patent Office to revoke the patent on any of the grounds upon which the grant of the patent could have been refused.
Where observations or an application for revocation are made under this section, the Patent Office shall notify the applicant or the patentee, and shall give him an opportunity to be heard before deciding the case.
Option 1 stipulates an ex-ante system of opposition. Under this system, the observations by third parties would be submitted after publication of the application and before granting of the patent. It is important in this case to make it clear that the examiner is obliged to take into consideration the observations made, either to admit or disregard them.
Option 2 provides for the revocation of a granted patent on the basis of administrative procedures. This would save challenging parties the cost of initiating a judicial procedure and in most cases speed resolution of challenges. Timing is crucial in resolving patent challenges, since the patents are presumed valid until revoked.