AirAsia X have yet to formally announce anything but the flight will operate between the Gold Coast and Christchurch as an addition to their daily KUL-OOL service. This has been covered in the Gold Coast Bulletin (I am unable to provide a link) and also mentioned in the Christchurch Press HERE
Malaysian (MH) have announced the desire to add a new NZ route, which is expected to be CHC, it is also expected to operate KUL-XXX-CHC with the mid point being one of the current Australian destinations.
The following quote comes from MH's chief executive officer/managing director Tengku Datuk Azmil Zahruddin
We will introduce new direct service to Brisbane and announce a new destination to New Zealand soonFrom this NEWS ITEM
This would bring the number of foreign carriers (non NZ or AU) on the tasman to 6 and the number of international carriers (non NZ) also operating to CHC to 6.
Foreign carriers currently operating on the tasman
Emirates - 4x daily return BNE-AKL, MEL-AKL, SYD-AKL, SYD-CHC
Lan - 6x weekly return AKL-SYD
Aerolineas Argentineas - 5x weekly return AKL-SYD
Royal Brunei - daily 1way service 4x AKL-BNE, 3x BNE-AKL - soon to be dropped to operate direct BWN-AKL-BWN
International carriers currently serving CHC