Off the top of my head and without actually having any facts, as per usual, they are court order enforcers and deal with court ordered debt repayment, confiscation of goods in lieu and the collection of overdue government and local council fines. They have quite a lot of power.
My only experience of them until now was a couple of years ago when I saw their van set up in Prahran supermarket carpark. They were noting number plates and 'having a word' to the owners, to say the least.
I saw a car in a side street in Malvern during the week. It had a huge yellow sticker over the front windscreen and another over the side window. I assumed it was an abandoned car and that the stickers had been placed by the local council. However by this picture published in The Herald Sun, I now know who put it there.
'Tis the Sheriff wot dun it. I ought to have looked down at the car's wheels.
So are as I know, only the Sheriff has the power to clamp a car's wheels, and then only since a legislative change a year ago. And clamping they have been doing. If you are owing over $1,000 in parking and traffic fines, expect the Sheriff to clamp your car if he notices it and you will then have negotiate repayment of the fines before your car is freed.
In absolute glee, I notice that the Sheriff has clamped some expensive European made cars.