Open Question: Legal work start times and clocking in?

If you are scheduled to start work at a certain time, is it legal for them to have you sit around off the clock and wait till they need you? I just started my first job as wait staff at a restaurant. I was under the impression this was a part time job as it was advertised for lunch or dinner shifts. However when I got to work yesterday at noon I wasn't allowed to clock on for almost 45 minutes. Then I was sent on a 2 hour break from 3-5pm. Upon returning at 5 I was made to sit and wait again before clocking on. Then I learned all shifts were 11 hours (scheduled) but in all actuality you will only work/be paid for 6-7 hours. So my rostered hours are well over what would be considered full time but the actual hours on the clock would be considered part time. Talking to several others on staff... they all said this is the norm for this place. I'm just wondering if its legal. I should state I am in Australia and not sure how their labour laws here work. :(