Flights to Wellington, the third largest city in New Zealand, are rarely anything approaching cheap, due to the enormous distance involved. However, if you are as flexible as possible with when you go and the route you take, you may be able to take advantage of a very reasonable deal. The airplane has to stop once along the way and there are many options.
Qantas.com, home to the national carrier of Australia, has flights from from London Heathrow direct to Wellington, stopping for a few hours along the way for the plane to refuel. Prices for a return ticket start at £980 if you take advantage of their special offers. Prices can be considerably higher if you are not as flexible as possible with your travelling times.
Air New Zealand offer some similar prices as well, often having some of the best rates for flights to Wellington. You can find out more about their ticket prices and special offers at their European portal, airnewzealand.eu. Prices for a return economy ticket start at £945, if you take advantage of one of their frequent special offers. Again, you will have to be as flexible as possible to take advantage of such a deal.
Other sites such as opodo.com or skyscanner.com are sometimes useful for finding the best deals on flights around the world. They compare ticket prices from all of the airlines connecting to Wellington. This allows you to find the best deal although, in some cases, the information is outdated.