OC ignores ByLaw trangressions; s65A alterations/additions to common property

What happens when owner(s) alter/add to common property without the permission and the EC/OC won’t do anything, including enforcing relevant bylaws.

Let’s assume the s65A threshold is reached with the works – replacing common property windows and doors, installing walls and windbreaks.

In our building 50% of owners have performed such works, obviously a majority vote to enforce bylaws is not a popular concept!

In the absence of a proactive OC, does it always require one owner to take another owner to the NCAT for breach of bylaws? Are there circumstances where the OC/EC ‘must’ enforce bylaws; alternatively when would the OC turning a blind eye to s65A common property breaches reach a threshold for an order against the owners corporation. What would that order be? Is anyone aware of any such cases?