Ah, the old “it’s a strata issue” excuse. First of all, your landlord needs to put a rocket up the strata manager for treating you (and there for the owner) like second-class citizens.
Secondly, sending miscreants feeble warnings then not following them up, simply encourages them to behave even worse.
So I would begin by telling the strata manager that you are reluctantly taking the owners corporation to NCAT because of their inaction, with a letter copied to the chair. In a situation where the chair is not resident, it should be expected that the strata manager would be reasonably didligent in protecting the interests of all residents. This would be under section 232.2 of the Act – failure to fulfil their (the owners corproation’s) duties (see below).
You will have to undertake mediation (which is free) before you can proceed to NCAT, but that might be enough of a scare in itself. If need be, you can pursue this to NCAT asking the Tribunal to compel the OC to take all reasonable steps to deal with an issue that they have conceded is a problem for you.
Another option would be to take action directly against the neighbours under section 153, but that puts you directly in the firing line with little or no support to be expected from the owners corp
(1) Orders relating to complaints and disputes The Tribunal may, on application by an interested person, original owner or building manager, make an order to settle a complaint or dispute about any of the following—
(2) Failure to exercise a function For the purposes of this section, an owners corporation, strata committee or building management committee is taken not to have exercised a function if—
(a) it decides not to exercise the function, or
(b) application is made to it to exercise the function and it fails for 2 months after the making of the application to exercise the function in accordance with the application or to inform the applicant that it has decided not to exercise the function in accordance with the application.
By the way, as a tenant, you are legally an “interested person” and entitled to pursue this case.