Tax in New Zealand is fairly straightforward. The main types of tax are GST (Goods & Service Tax) and Income Tax with most tax in New Zealand being deducted at source, whether that source be your income, or an item you are buying in a shop. Most people in New Zealand only need to complete a tax return if they have additional income to declare that is not covered by PAYE (pay as you earn) such as rental income, or if they are subject to business taxes.
For the average worker the tax in NZ is not particularly high, but due to the income banding method of calculation it can be quite steep for those on a higher income. That said, the level of taxation is on a par with other countries with similar forms of taxation, however, it is higher than the UK and Australia.