The reality of renting, of being a tenant, is that you are, somewhat, at the mercy of fate when it comes to who your neighbours are and how they may behave. You may, for instance, discover, only upon moving into an apartment, that your next door neighbours are pest-attracting hoarders, have a hundred cats, or even run a brothel from their apartment. In circumstances, such as these, you may complain to authorities, like local government agencies and, even, the police, but this will not guarantee that your landlord, or landlady, will allow you to cancel a tenancy, which has time to run.
At least, not in the short-term, that is, repeated complaints to relevant authorities, which are well documented, may, eventually, result in a sympathetic hearing from property managers and owners, but there is no guarantee. Tenancy laws in Australia are under the jurisdiction of the states; in NSW the only relevant breach by the owner of the property, which possibly could be used to get a lease cancelled is that the premises is unliveable. Tenants would need to prove that the property has become unliveable due to the behaviour of the neighbours; this would not be easy.
Vermin would have to be a major issue in the case of unhygienic practices by neighbours. In the case of a brothel running next door, safety and security could be mounted as an issue, but well documented evidence would need to be provided, backed up by Council and police. In the instance of a variety of high-class escorts going to and from the apartment all day, this may not justify enough of a real and present danger. It would more likely be successful if there were a lot of men hanging around the building, and that the tenants complaining had children.
In Australia, property owners are kings and queens, the humble tenant has few rights when compared to renters in parts of Europe; where home ownership is rarer. Home ownership in Australia is a holy grail and real estate investors are protected by laws, which encourage more investing at the expense of tenant’s rights. Recently, a friend of mine who had lived in the same building as a tenant for twenty years was given a few weeks’ notice to vacate his home; I use the term home to reflect his emotional attachment to his apartment. This would not happen in France, where long term renters have rights, protecting their attachment to their homes; despite the fact that they do not own the property. My friend, committed suicide shortly after his evacuation of his long term abode, I am not saying that there were no other issues involved but it certainly didn’t help.