Only do this less than 30 days before travel, then you take the DSLR with you and claim back the GST. I believe that the prices might be a bit more than HK but the again you will still have access to an AUS warranty etc.
Yes I've been looking at a few of the local & reputable online shops, there is still about a $200 AUD saving in HK but after GST the difference may not be worth the hassle. Not worried about the tourist scheme as I'll claim the GST back through my business anyway, better than having to lug an extra DSLR out of the country.