Homeless is an ill defined term. The definition used by governments and NGOs is different from the one used by everyone else. The former seem to deliberately lean in to the confusion in order to tie policy goals related to their more expansive definition to the greater public interest in solving the narrower problem.

In any event, it doesn’t take very many homeless by the colloquial definition to make a city unpleasant. I don’t know whether or not Sydney has a homelessness problem and that link doesn’t tell me.