Oops- sorry just re-read the post re: IRD #'s. It look slike you can apply for an IRD # from overseas as long as you have some type of NZ visa stamped in your passport. See below (from the Inland Revenue website):
Overseas passport with New Zealand immigration visa / permit (please photocopy the pages showing photo, name, any pages showing current work, visitor permits, or residency documentation and a specimen signature) or call Inland Revenue on 0800 227 774 for exempt list
Arrived in Auckland Oct 19, 2006...and left August 5, 2007...came back to NZ in July 10, 2011!