Apple may restrict Hardware Service and ADH Services to the country where the Covered Equipment was originally purchased.
And even the AppleCare+ page says "Service coverage may be subject to certain restrictions."
Hopefully you will not have any issues :)
Oh, but AppleCare+ is pretty awesome when you are in a country where they can handle it.
I really doubt you would have problems getting Apple to deal with AppleCare+ services for AU bought equipment here in NZ.
Had a phone bought from Apple NZ that had its screen shatter when I was in Norway (mea culpa). They couldn't handle it in Norway, but when I took it to Scotland they replaced the phone *for free*, no charge because they weren't able to charge the cost of the AppleCare+ replacement phone in NZD (apparently, at least at the time, they were only able to charge for services in the same currency as the AppleCare+).
Have not had any problems having Apple cover a MacBook bought in Norway with AppleCare here in New Zealand either.
So in my experience it works pretty well.