firstly, you have no financial burden in HK after you resigned the job. If you always remember the $$$, you would not relax and enjoy the trip.
I went to Perth with working holiday in two years ago and I was lucky to have a farm job and earn around AUD450-500 doller per week, so the monthly paid is around $13000. However you have to pay accommodation and daily expenses. So I think the earning is enough for your stay in australia and travel around. The travel cost in Australia is quite expensive, normally AUD99 for day trip.
If you want to earn money more than HK, I think it would be but you would not enjoy the trip and travel around.