Can I buy guns in New Zealand? NZ requires all firearms owners to obtain a license, which requires a background check, references, and a short knowledge and safety test. If you plan on bringing guns into the country make inquiries beforehand: you need a permit and temporary license to bring a rifle in on a temporary hunting trip, not sure about bringing them in if you're moving here.
If what you want is a rifle or shotgun, you will need to get a firearms license, have your house inspected to make sure you have a safe place to keep it (i.e. locked cupboard, safe or similar), and in some cases occasional inspections. They can only be owned for hunting purposes, farm usefulness or target shooting - firearms are not permitted for the purpose of personal defence. Firearms must be stored unloaded and locked up with the bolt stored seperately.
NZ is very much pro gun compared to some countries (like Australia).
In NZ air guns (under a certain power) aren't considered firearms and can be bought by anyone over 18. In Australia they are considered cat A firearms, the same as a rimfire rifle or shotgun.
In NZ you can get a firearms license just by proving you are competent, and have somewhere safe to store it. In Australia you need a letter from a land owner or club allowing you to use the gun on their property (you still need to have somewhere to store it, but you don't need to prove you are competent).
In NZ you can buy a firearm and it is simply the sellers responsibility to check that you have a suitable license. In Australia all sales must be approved by the buyers local firearms officer and recorded on the buyers license.
In NZ semi-auto firearms are treated (almost) the same as a bolt action. In Australia semi-auto is allowed for some types of competition handgun and is practically impossible to get in rifles and shotguns unless you are a professional shooter. However, NZ also strictly regulates "Military Style Semi-Automatics," semiautomatics with a greater than 7 round magazine (15 for rimfires) or any one of a number of cosmetic features.
Handguns are very rare. You need a special sporting licence, where you have to be a proven active member of an approved shooting club and have an endorsement from the club. They must be transported in an approved lockbox and can never be stored in an operable condition. Basically, guns shorter than 30" aren't worth owning unless you're a serious target shooting enthusiast.
Silencers are completely unrestricted and commonly used for hunting rabbits, or just protecting people's hearing.