While the strict legal answer to this question is relatively simple, practicalities and the circumstances of the situation sometimes means that enforcement of a by-law is challenging. If a party simply wants to act unlawfully, ‘encouraging’ that party to behave according to the law may require steely determination on the part of the aggrieved persons including the payment of legal fees.
As to the legal process, if the owners corporation wishes to enforce a by-law there is a specific process set out in Section 146 of the Strata Schemes Management Act 2015. That section permits a form of Notice to Comply to be served, in the approved form, on the apparently offending owner, by the managing strata agent, or after a regular resolution by the Owners approving the notice.
If an individual owner (or group of owners) wishes to enforce a by-law the proper approach is to make a formal request to the Strata Manager to serve the Section 45. The Strata Manager should take the steps delegated to them to obtain authority to send the Notice. If nothing eventuates, then the owner should call a meeting of the Executive Committee (or the Owners Corporation), proposing a motion to serve the Section 45 Notice.
If, after service of the notice the offending owner fails to comply with the by-law, NCAT may impose a civil penalty on that owner of up to 10 penalty units (over $1000) under Section 147 of the Act. NCAT can also impose adverse costs orders on the offending owner under section 147. The application must be made within 12 months of the service of the notice.
(As always there are strict requirements for service of documents by or on the Owners Corporation under the Act which must be closely followed.)