Don't break your lease without talking to Fair Trading on 13 32 20 first.
However, why be driven out of your home?
There are plenty of simple ways that this pool could be locked down at night – electronic locks, timers on the lights, security cameras and motion sensors – none of which are terribly expensive.
But you need to get your landlord to drive this issue and he needs to take it up with the strata manager and executive committee and do so without delay.
Otherwise youcould go to Fair Trading and not only demand that he fixes the problem, but ask for compensation too.
However, it's in your landlord's best interests to get this fixed now before it seriously damages the value of his property.