Flight to australia

can anyone in this forum suggest me about the cheapest flight route,from Tokyo to Canberra,Australia? I searched in the internet,but got confused. There is huge difference between flight price from a)Tokyo to Canberra and b)Tokyo to Sydney? Will it be more cheap,if I take flight from Tokyo to Sydney,then from there to Canberra by some other means like train? I will be so grateful,if someone in this forum can help me with some advice.
Thanks
Prakash