I HIGHLY doubt it. I've never ever heard of credit scores following people to other countries. The idea itself is rather absurd - different countries have different methods of calculation and use different scales. So, no, I don't think your Canadian credit score will follow you to Australia.
Why would you want to keep credit card balances unpaid? It will grow more debit interest and financial fees! Doesn't make sense! What if you forgot to pay before the due date? If you want to keep the credit card, why don't you just payoff and then use the card in your new country?