"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.