Yesterday I learned that private security guards, armed with guns, have been employed by Melbourne city council to move homeless people on.
Basically, City of Melbourne has employed armed goons to bully our city's most vulnerable people, so that business doesn't suffer and the rest of us don't have to feel weird.
They don't have any specific power to use force, beyond the citizens arrest power we all share.
I don't know how they've been allowed weapons, given I can't imagine a situation where they could be used that wasn't caused directly by incompetence on the part of the security guard.