I just booked an AKL-SIN-TPE ticket with about a 40 hour layover on purpose, to take advantage of 2 nights in SIN. Just look closely at the details of your flight options and pick one that suits you. My ticket cost no more than the other flight options with shorter layovers. Once the booking was complete, there was an area in "Manage booking" to book a stopover hotel package. Cheaper options can be found on your own, however.