I'd say the Owners Corporation has to fix it under their legal obligation to maintain and repair common property and then they can try to get the money out of a) the police (for breaking it) or b) the owner (for leaving their stereo on too loud).
a) Would mean a fairly frosty reception from NSW's finest the next time there's a genuine emergency
b) would mean a lot of hassle with no guarantee of a result worth pursuing (since you can't get costs awarded at the CTTT)
So, if they've got any sense, they'll put it down part of life's rich tapestry and be grateful there wasn't a dead body in there. That's probably not the strictly legal answer but I reckon it's the most pragmatic.
Oh, and set up a register of who's got residents' spare keys.