A cruise ship passenger is missing, believed overboard, near Mahia Peninsula, on the east coast of the North Island.
Emergency services are searching the waters for a male missing from the Norwegian Jewel from around 7pm on Sunday evening, said Rescue Co-ordination Centre spokesman Vince Cholewa.
An Air Force NH90 helicopter has been called in from Ohakea, and continued the search overnight using sophisticated heat-sensing equipment.
A container ship was using powerful search lights in the rescue efforts led by Maritime New Zealand, Cholewa said early on Sunday evening.
"The sea state is good for searching, however the concern is the approaching darkness."
The Norwegian Jewel is six nautical miles southwest of Mahia Peninsula and is going through an overboard procedure and counting those aboard.
Staff on the vessel were reviewing CCTV footage as well as searching onboard for the missing man, Cholewa said.
The Jewel can carry up to 2376 passengers and is 965 feet (294m) long, the Norwegian Cruise Line website said.
Two yachts earlier responded to the event but one has been released from the search.
One chopper from Hawke's Bay Rescue Helicopter Trust and another from Eastland Rescue Trust earlier searched for the missing passenger, but have since returned to their stations.