Timbeck sells Western Red Cedar in 6 meter lengths. I bought quite a bit of them. They were very helpful choosing the best pieces from their stock.

Their agent in WA is Austim. I would give them a try.

Also Paulownia is worth looking at, I haven't used it but I know a few people who have with great success.

: Hi everyone,

: I'm a first time builder looking for a good project for this year.
: I've settled on building the high capacity Great Auk from
: Guillemot Kayaks for my first, really looking forward to getting
: started. The only issue that I've run into is that I live in
: Perth (Western Australia), and from what I can see so far almost
: everyone on this site is on the other side of the world and I
: was hoping to ask for any experience with Australian timber...

: So far I have identified three possibilities. I am able to get
: Western Red Cedar imported, but only in 3m lengths. Besides
: Pine, the only other wood appropriate is Tasmanian Oak, but it
: is about twice the density of the cedar. I have also been
: informed that the available pine suffers from a black
: mould/fungus which appears in the prescence of water - I have
: seen this on other boats, but I think it probably only happens
: when the boats are in the water full-time. I'd like to have pine
: as an option, as it is much cheaper, comes in any length I want
: and will stain very well. Otherwise I'll have to scarf the cedar
: or try and find some long planks of the tassie oak.

: Graham