Do you have an Air NZ account? According to their website you can only earn Air NZ points on Cathay for HKG to NZ, so you will not be eligible to earn points on your trip.
http://www.airnewzealand.co.uk/co-op...cathay-pacific
By AE Plat do you mean American Express? You can't earn MR points by flying, only through purchase.
Do you collect frequent flyer miles in any programs currently? You can credit the CX flights to any oneworld program or certain CX partners.