AI is partly right. There is a clause in strata law that says common property must be repaired and maintained – by the owners, not the strata manager.
Section 106 says:
(1) An owners corporation for a strata scheme must properly maintain and keep in a state of good and serviceable repair the common property and any personal property vested in the owners corporation.
That section also allows some exclusions, but only if it would be inappropriate to undertake the repairs (whatever that means) and inaction wouldn’t affect the safety or appearance of the building.
The strata manager can pretty much only do what the strata scheme asks them to do, so expecting them to be proactive is a little misdirected. They should, however, be offering advice on what you can do to resolve this.
If the owner refuses to allow the work to be done, the OC could seek mediation and Tribunal orders under section 122 which can lead to the lot owner being required to allow access for work that needs to be done under the terms of the Act.