That’s a tricky one. The real estate agent is not the party collecting the information, which is where the Privacy Act obligations usually start. So the $3 million turnover question is moot.
However, the disclosure of the strata roll information by the strata manager is permitted to the extent it is required or authorised by law. In this case you can disclose it for purposes within the Strata Schemes Management Act – it’s reasonable to say what the real estate agent is doing is outside those parameters.
That leaves you with the issue of how you control a third party using information in this way. I suggest you contact the strata manager and ask them to tell the real estate agent that use of the information in this way is not acceptable and he should cease immediately. You could also tell the real estate agent he is doing more damage to his business than good.