The person died yesterday as Ovation of the Seas sailed from Sydney towards Bay of Islands, operator Royal Caribbean has confirmed.
The ship is due in Dunedin on February 9 after a few North Island stops.
There had been speculation on social media that the passenger had flu-like symptoms and the death could be linked to the deadly coronavirus.
But Royal Caribbean has ruled this out, saying it was from natural causes and unrelated to the global outbreak.
A Royal Caribbean spokesperson said the dead passenger's family had been informed and the company was providing them with assistance during this difficult time.
While the death was unrelated to coronavirus, Royal Caribbean said it was taking precautions to protect the health and safety of guests and crew on all its ships.
The measures included blocking any individual who had travelled from, to or through mainland China or Hong Kong in the past 15 days from boarding the ship, and screening guests who had been in contact with people who had traveled to or through mainland China or Hong Kong in the past 15 days, and all holders of China or Hong Kong passports.
All cruises sailing through China and Hong Kong had also been cancelled until the end of February.
A police spokesperson confirmed police were notified yesterday of a sudden death on board a cruise ship bound for Northland.
A Maritime NZ spokesperson said it was aware of the death on the Ovation of the Seas, but police were now dealing with the matter.
Ovation of the Seas left from Sydney and is due to dock in the Bay of Islands tomorrow before arriving in Tauranga on Thursday.
Usual protocol would be for a police officer and doctor to meet the ship on its arrival if a person had died from a medical event.
Ovation of the Seas was the cruise liner carrying passengers injured in the devastating White Island volcanic eruption in December.
The ship had been docked in Tauranga while some passengers opted to go on a tour of the live volcano.
There were 47 people on the island at the time and 21 were killed and 26 injured in the eruption, with many suffering serious burns.
