You need to look at more than just the initial cost of obtaining the licence unless you plan to work only in New Zealand after. Commercial helicopter jobs in New Zealand are very scarce so you need to know what to do to convert a New Zealand CPL into a licence you can use in another country.
I see from your profile that you are from UK and if the rules are still as they were when I was involved in ab-initio training (quite some years ago now), you may well find that if you wish to work in UK you will still have to do 50 hours flying, pass the GFTs here and do some or all of the ground exams here too.
Although it may not be quite as cheap, you may well be better off going to a school in USA where you can work towards FAA/CAA and JAR licences. HAI in Florida (with whom I have no personal ties) offer approved training for all 3 of the previously managed licences and have both British and American flight and ground insructors.
You may well find out that this is the overall cheaper option if you have any thoughts of working in Europe or the USA. The CAA and FAA licences are also accepted by many countries if you later wish to work overseas.