From NZ Herald and thanks to TA from OzBargain for the tip.
Air New Zealand is pleased to announce the return of Night Rider!
Our special late night service offers $29 fares for every seat on the plane and will operate to selected domestic destinations on the Air New Zealand network.
Auckland - Christchurch and Auckland - Nelson are the first to enjoy Night Rider’s low fares.
Book now - Fly between 20th Feb 2015 - 19th Mar 2015.
*Available on selected Domestic nonstop flights and routes only, which are subject to change. Seats are strictly limited and may not be available on all flights or all dates. During special events or holiday periods these fares are particularly limited and will sell quickly. Flexitime and Flexiplus fares are not available. Card payment fee of $4pp per one-way journey applies. The "Seat" option includes a carry-on bag (up to 7kg) but no checked baggage. For bookings made through our Contact Centre or Air NZ Holidays Stores a non-refundable service fee of $30 per person per one-way Domestic journey applies. HVC benefits are not applicable on Night Rider services.
Interesting they have brought it back, but no WLG flights makes this virtually a waste of time to most I'd imagine.