Water leaks/owner’s rights

Hi,
 
I bought a unit in the Sydney CBD area nearly 9 years ago and currently rent it out.  Several years ago a number of water leaks started up in the building, which is about 9 or 10 stories high.  A large amount of money was spent waterproofing each floor through the then HIH rescue package.  Apparently an assessor from the Fair Trading Dept was sent out and approved works to occur at that time several years ago.
 
To cut a long story short, for the last 3 years, on and off, my unit has had water coming through from the unit above, in several areas.  The Strata managers contract a building manager to work onsite and he liaises with the tenants and plumbers to arrange access etc. 
 
My issue is that these water leaks have been going on for 3 years and they don’t appear to be being fixed.  I use a managing agent to manage the unit but I was recently forced to become involved directly because of the ongoing water issues re-occurring.  I ended up sending an email direct to the strata managers and they advised that when the waterproofing occurred 3 years ago, the assessor from Fair Trading only approved for PART of the area in the unit above mine to be waterproofed.  I might be off the mark, but I would have thought that after a year or so of the leaks continuing, someone from the strata managers should have realised that maybe the leaks are occurring because the unit above was only partly waterproofed.  I had always been under the impression that the whole unit above had been waterproofed.  When I received the email I immediately wrote back and said that in my view, doing only part of the above floor was negligent – it’s like doing half a job. 
 
The current situation is that the strata managers have sent an urgent request to the Fair Trading Dep’t asking for the original works job to be resurrected and for further waterproofing to occur.
 
Over the last 3 years I have had to grant rent reductions to the tenants because of the leaks.  I am currently giving the tenants a rent reduction because of the current water leaks.  Under the circumstances, can I claim compensation?  and if so, which tribunal should I approach and who can I claim compensation from to re-in burse me for lost rent.  I was thinking that the strata managers may have sat on this information for too long before deciding to try and get the original works continued!  Also, if the Dep’t of Fair Trading refuses to resurrect the original works job, who would be paying for repairs?  Would I personally be up for repair costs? 
 
Can you advise me please as I probably won’t be able to continue to offer the rent reduction?
 
Thanks for your time
Regards