You can get the discounts through any travel agent. My personal opinoin is to use a local cruise experince travel agent. You "will" get the same rate but you will get that personal service also and thats a big part of crusing is the service. My last few cruises I actually booked on the ship and got a great onboard credit. But since you will not be on a ship to arrange your next cruise I do recommend the local agent also the local guy since you live in New Zealand will know all of the leaving and re-entering procedures for your country and will be more Familiar with your airline traffic.