Which way does the balcony face and how much sun does it get during the day? That will determine what plants might do well there.

it faces a north west direction and tends to get morning and afternoon sun but shade in the late afternoon and evening.

since you are down under, you'll need to figure out approx your climate zone and tell us. otherwise we won't know what your climate conditions are like. not just hardiness zone. sunset zone is much more informative. they only have it for US, but you should be able to find smth similar to your conditions, at least approximately.
http://planthardiness.ars.usda.gov/PHZMWeb/

Here is a link that might be useful: sunset climate zones