For jobs in general check out
www.seek.com.au
If you want to know the best places for engineering jobs do the same search in several different locations and see where all the jobs are.
My husband is a mining engineer and he's working in Brisbane, which is odd because there are no mines in Brisbane. So there are lots of jobs here too. I know of 3 people whose husbands are engieers in my area, one civil one mechanical.
We have a permanent visa so work may have been easier to find for us. What kind of visa are you coming in? If you're coming on a holiday visa then it might be harder to get employment because you can't stay in one place longer than 6 months. They could chose to sponsor you for a visa to allow you to stay longer though. But it would just be that initial hurdle finding an employeer with that visa.
If you're coming on a temp visa then it should be easier. As far as I know you won't have to be a member of any organizations to practice. We did need to get a skills assessment from Engineers Australia for our visa application (for permanent residents). But once we arrived my husband has worked without being registered anywhere. Here when they graduate they can use the title "Engineer" without a problem, not like Canada.