Auckland -> Adelaide, Brisbane, Cairns, Gold Coast, Hamilton Island, Mackay, Melbourne, Sydney, Townsville, Whitsunday Coast Christchurch -> Adelaide, Ballina Byron, Brisbane, Cairns, Gold Coast, Hamilton Island, Hobart, Launceston, Mackay, Melbourne, Perth, Sydney & Townsville Wellington -> Brisbane, Cairns, Hamilton Island, Melbourne, Perth, Sydney
Even though Air New Zealand are not classed as a budget airline, over recent years their prices have become much more competitive so its also worth checking out www.airnewzealand.co.nz
From the Rest of the World:
Sydney and Perth are on the flight routes of the majority of the main airlines. The best thing to do is check your local travel agent or favourite flights website to get the best deals. You will have two major decisions which will vary depending on where you fly from:
Direct Flight or Round The World Pass - When purchasing your fligt to OZ you have the option to buy one that just takes you straight there. Although if you are flying from Europe it will stop to refuel you will get on at your destination and get off in Australia. With some direct flights you have the option to add on a stopover. This is a good idea if you don't like long flights as it breaks up the journey. Its also a great opportunity to exlpore places such as LA, Singapore and Hong Kong!
Alternatively you can buy your flight to Australia as part of a round the world ticket (RTW). These basically combine a number of different flights together which will take you right around the world. For example you can get flights that go London -> LA -> Fiji -> Auckland -> Sydney -> Perth -> Singapore -> London. There are loads of different options so you can create your own unique journey! RTW tickets are also much more flexible than direct tickets, allowing you to make changes as you travel. So if you fall in love with Australia you can stay longer!!