The current El Nino weather phenomenon could be one of the strongest on record, the World Meteorological Organisation says.
The event occurs when the waters of the Pacific become exceptionally warm and distort weather patterns around the world.
The World Meteorological Organisation said the event now underway was sending sea temperatures in parts of the Pacific to levels not seen since the late 1990s and could be among the four strongest events since 1950.
NIWA said an intense El Nino did not necessarily mean there would be intense weather events in New Zealand, however, and it would depend on other climatic variables.