All downlights installed in NZ must comply with the Standard AS/NZS 60598.2.2 plus amendment A. The importers or manufacturers must have their downlights tested by an independent laboratory to check that they meet the standard and also to obtain an insulation rating.
Proof of compliance is held by the importer or manufacturer, and on the basis of this they issue a Statutory Declaration of Compliance (SDoC). Council inspectors may ask for the SDoC but well known brands are usually accepted without question. If you need an SDoC email your supplier.
The insulation rating is IC or IC-F. The IC-F rating is a NZ only rating that means that the downlight can be installed under insulation that is only rated to 90 degrees C.and also that the light is sealed so insulation cannot get into the fitting.
In effect IC and IC-F are both fine unless your insulation is an unusual type.
The Standard also specifies the information to be given in the installation instructions. Required information is the side and vertical distances that must be maintained from a building element. Apart from the obvious fire danger the increased heat will shorten the life of the LED.
All of the information you will need should be in the instructions or on the box.
If you need more than this brief summary visit the Energy Safety website