Bugerion said:
Whoa, another South Australian? Hi. I could probably walk to your place from where I am, quite literally.
Pretty much what he said. It sums up education in Australia nicely, although other states have different variants of the high school diploma (Western Australia has WACE, etc).
I went to a rigorously competitive, ludicrously expensive private school. I regret nothing. The quality of my education there far surpassed what I remember from public school (although public education here is still leagues ahead of America), but that was also in part due to being an IB school.
Answering your question, public school and my non-IB years of high school had tolerable homework times. The International Baccelaureate is unforgiving, though: find the IB forums on the net and behold people from all over the world complaining about 6 or more hours of homework a night (you get nightly homework from every subject, and they ask you to devote about an hour a night per subject).
I'm at a law school now, entering second year. It's 80% homework and 20% school time (I only spend five hours a week at university, but have about 10 - 15 hours worth of reading and writing material for that week).