I started to play with AU traffic a bit and I see dramatically lower LP ctr rates than with US traffic for example, is this normal for this GEO? Im using the same LP that I was getting good results with US traffic, clickthru rate was above 30%, now in AU I see something like 12-15% on the same traffic sources. Banner CTRs are comparable tho, just the the LP ctr is totally off. Any input is appreciated 
Where is located your server? Do you use CDN?
Good call, the server is in the US. Strange enough tho, I also started a NZ and ZA campaign at the same time and the LP ctrs in the later two are just fine.
Not normal, unless the traffic source has a natural quality bias towards US traffic.
I usually find the opposite.
AU traffic, targeted well, draws a higher LP CTR than US traffic.
Are you committing any cultural faux-pas on the landing page?
e.g. Moms should be Mums...
Slap an Aussie flag on it while you're at it.
If your language is neutral, I would just launch a whole bunch of new LPs to see if one sticks.
Sometimes a LP that is fresh in one market can be done to death in another. It's usually the other way round between AU and US, but can still happen.