This posting (below, from kiwipaul) is wrong in two very significant ways. In NSW you do not require a vote of ALL owners except for a very, very few decisions – such as dissolving a strata plan or repaying overpaid levies – and this isn’t one of them.
The law (as quoted twice in this thread) allows the OC or its representatives to invest money that would otherwise sit in their bank accounts but, as ScotlandX says below, it has to be appropriate investment. If we needed unanimous votes for these most basic functions, nothing would ever get done.
Also, withholding your levies is not the smartest thing you can do in a dispute since it means you can’t vote or even propose a motion at a general meeting – some chairs would even use it as an excuse to prevent you from speaking – so you have effectively tied your own hands behind your back.
FYI: It’s a strata manager (or strata managing agent) in NSW and it’s an Owners’ Corporation, not a BC (Body Corporate).
If you want a definitive and reliable answer to this question it has already been provided below by ScotlandX.