hairy1: If you imported the item and paid GST when importing it (for instance DHL may collect GST on your behalf and charge you during the import process) then you can claim that but you purchased overseas and just brought it back into NZ then the answer is no.
As an aside ASUS just pushes out an OTA update for the transformer. The rumour is that it is prep for honeycomb 3.2. I installed it with no issues.
I put one in my Amazon checkout just to see what the costs were. Amazon added tax on the item when it was going to NZ. So as long as you can show that tax as a separate item you should be able to get the GST back if you qualify. The question is, will the Amazon invoice satisfy the IRD as a GST invoice which should show the collector's GST registration number.
Perhaps somebody who purchased one can provide more information.