I'm in France, and the minimum amount for people who don't work is 475€ / month. Although you can also get some money to help you with your rent if you don't live with friends or family. The amount you mention, AU$18 US$19 EU14.50 per day, translates to 435€ / month.
I can say without a doubt that yes, you CAN live off that amount. I know people who do, in fact. Usually, they live with friends & family, or they share cheap accomodation (which costs about 200€/month). I don't know about Australia, but it feels to me like it's much easier in France than, say for example America, to live with little money. You get free healthcare & free transportation, as well as support for your rent, up to about 200€ / month : you can't get the economy running if you're ill, can't go to your workplace or don't have a place to live.
Also, if you get a part-time job, your welfare does not go away. The amount of the welfare is incrementally reduced as your job's wage increases. It's a really powerful tool, because it means that you aren't deterred from working a few hours a week. Before we had that tool, it was more profitable for someone to not work than to work a few hours a week.
PS : i'm not trying to say my country is awesome and superior to any other, i'm just explaining how it works here, so that i can further explain why i believe you CAN live off 14.50€ / day.