There aren't really any restrictions on buying property or sections in NZ apart from in certain 'choice' positions which is, I believe, to do with preventing outside property developers snapping up the best bits of land and turning them into housing estates. There may be a limit to the size of section you can buy but you should be able to get a few acres without too much trouble. Quite a few immigrants have set themselves up with rearing a few animals so it can be done.

If you want to start what would be called a smallholding in the UK, you could look for a lifestyle block which usually has a house on it and possibly some useful outbuildings. Otherwise, there are sections up for sale where you can build your own house. Often the services i.e. electricity, water and phone are available at the gate of the section and you would be responsible for bringing them onto your land and connecting them up. If the section you buy isn't on mains water, and a lot of rural sections in NZ aren't, you would need to look into having rainwater tanks installed as well, which adds a great deal to the original cost of the section. Another item to consider is a septic tank or cesspit if the section isn't on mains drainage.

If you take a look at Glenda's house building thread, she gives a good account of some of the costs involved when you start from scratch.