The man, who is believed to be in his 80s, suffered a medical event while the Princess Cruises ship was docked at Napier Port.
An ambulance and police attended the liner, but the passenger was unable to be revived.
A spokesperson for Carnival Australia, accounting for a number of cruise companies including Princess, confirmed that the medical team of Diamond Princess had assisted an elderly passenger who experienced a medical event while the vessel was visiting Napier on Thursday.
The spokesman said an accident of the kind was relatively infrequent, with over 20 million people worldwide cruising annually.
Diamond Princess departed for Tauranga shortly after the death.