I really like contactless payment, like most people I wish NZ Banks had implemented a more elegant solution than sticking a card to your phone but that's all we have at the moment so for anyone interested who doesn't want to "uglify" their phone / case with a stick on ASB PayTag here is what I have done with mine.

I have an iPhone 6, I got it on launch day and the only case I could find was the Incipio dual pro. It has a layer of silicon and then a layer of a hard outer shell on top. I thought it would be a good interim case but I liked it so much I still use it.

I cut a hole in the inner rubber bit the size of the PayTag, then inserted the PayTag which is almost exactly the same thickness as the inner rubber. No need to stick it to your phone, I just put the outer shell on which hold's it firmly in place. 

I've been out using it the last couple of days and it works great. No issues.