Contact Jetstar with your flight details and they should allocate you a seat - for a fee!

(Do a dummy booking on the same flight to pull up a seat map.)

Even though a BP may print out on check-in for AKL-ZQN, they are unlikely to give it to you. Online check-in won't work either: http://www.qantas.com.au/travel/airl...able/global/en