You can trap the cat and warn the owner or handover to the local council.
You can borrow a trapping cage from local council/shire or buy a one for thirty bucks.
http://www.ebay.com.au/itm/Medium-Hu...4AAOSwF6dZccW1
Just make sure you're home to attend the trapped cat.
It cost money for the owner to retrieve the cat from the local pound, so it is a lesson, for starters.