I'm not sure how it applies to a spouse temp visa. I know on the 457 temp you don't get medicare.
You'll have to check the Medicare website to be sure. I had a quick look but I didn't see anything on that page that specifically mentioned spouse visas.
http://www.medicareaustralia.gov.au/pub ... bility.jsp
I know that if you are in Oz on a temp visa you can get medicare as soon as you apply for a permanent visa. But that probably won't help you initially. I suggest having a good look around that site and if necessary call the Medicare office to find out.
If you have
UK citizenship then you would be covered under a reciprocal agreement. Unfortunately there is no such agreement for Canada. So you either have to be covered under Medicare or take out private health insurance.