Most NZ councils will only allow up to 10m² of floor area and up to 3.5m of height above the floor level before you require a permit. Check with your local council on what is allowed in your area. If you have a Body Corporate / Cross-lease or live in a Historic area you should check on that too.
Permits may mean a resource consent plus building consent, this can be time consuming and costly. Height to Boundary rules – Usually a shed is meant to be the height of the wall away from the boundary (“height to boundary”). If you are wanting to put the shed on or closer to the boundary than this you should first check with your neighbour, and the council.