Thise restrooms with sharps bins are handily identified on maps.
https://toiletmap.gov.au/Mobile?state=New%20South%20Wales&lo...
It's part of the (I think) community sharps disposal programme. http://www.communitysharps.org.au/resources/disposal-options
People addicted to drugs take drugs. We need to recognise that, and reduce the harm they do to others. Needle-stick injuries are a significant concern to a wide range of low pay workers, so better needle disposal programmes are a good idea.