Voltage * Frequency * Plug Shape
The New Zealand electricity supply is 240 volts, 50 hertz. Your electrical equipment should work here if you come from The UK, continental Europe, South Africa, South Korea, India, China, Russia or Malaysia.
Be aware that electrical devices in New Zealand are rated for a maximum of 10 amps. If you have high power devices which operate at currents greater than 10 amps these will not operate safely in New Zealand. (In countries such as the UK some devices operate at up to 13 amps.)
You will usually need to fit new plugs to your equipment because New Zealand plugs are most likely shaped differently from those in your country. A good tip is to bring 4-socket extension boards and fit a New Zealand plug to each board. In this way, you will be saved from putting new plugs on irons, kettles, toasters, computers, Hi-Fi’s, etc. Keep the old plugs on them and plug them into the extension board.
If you come from a country with a 100 – 120 V supply, first check if any of your equipment can be switched to 240 V operation.
If it cannot, it will need an electrical transformer to work in New Zealand. This is an expensive solution and you are probably best to sell the equipment before you leave and replace it when you get to New Zealand.
Your electrical equipment will need to be modified if you come from The US, Canada, Japan, Taiwan and most of Latin America.
Have a look at this useful map below. You can see that New Zealand is in the blue zone of countries with mains supply of 220 – 240 V and 50 Hz. General electrical equipment from one “blue” country will work in every other “blue” country provided it’s got the correct shaped plug on it.