We seem to carry quite alot of pax from LHR-LAX who then connect onto NZ1 LAX-AKL which always baffles me as NZ1 starts at LHR anyway. I often wondered if it was cheaper to do it that way which is why they are doing it as aside from the LHR-LAX bit being full, I don't see any other reason.
You could always go via Sydney/Brisbane/Melbourne and then hop across to Christchurch on PacificBlue too.
If you book with certain airlines, often a stop over is allowed in the fare, either on one sector or sometimes both. The only extra it would cost then is the cost of a hotel in the city you choose.
Have you spoken to Austravel ?. They are specialists in OZ and NZ flights etc.
Often it can work out cheaper to book the flights through a company such as Austravel as they may have access to fares that are not onsale to the public directly from the airlines.
