Yes I get that and that's what I've been doing so far. But my Canadian passport is expiring in January so there will be a 2-3 month period during which if I have to go to the US, I have to use the Australian passport. And I will likely need to do that.

The last time I renewed my Canadian passport I sent it off in November and asked for expedited service (paying the fee, I might add), requesting it in time for a Christmas flight - it came at the end of January.

There is no Canadian consulate on the island, I must send the passport up to Ottawa to get renewed.