One of the key aspects of buying a home is making sure that it checks out. Many houses in New Zealand do have renovations or additions that might not carry the proper permits. This can have an impact on future salability and also the lender requirements. However many minor issues can be bankable and insurable.
It is always smart to check with your own legal adviser about other legal implications.
Is it insurable?
It is important to make honest disclosures when you are taking insurance to ensure that you understand what you are covered for. In many instances insurance may be possible, but often the unconsented works will not be covered or getting it to code will not be covered.
Brent explains further in this clip.