Widespread rain is expected to fall in New Zealand on Tuesday with heavy falls likely to continue into Wednesday.
A large low is expected to bring wet weather and "varying surges" of wind in some regions - mainly in the North Island and upper South Island.
WeatherWatch says clouds will begin to thicken on Tuesday, with the forecaster predicting rain to start spreading down the country.
"This is an evolving situation," the forecaster said in a statement.
"After this event, we have more windy weather through the upcoming weekend."
Heavy rain warnings are in place for Taranaki north of Eltham and Bay of Plenty. National forecaster MetService expects 80-100mm of rain in those regions between 1am and 7pm on Wednesday.
NIWA says this particular weather system is a characteristic of La Niña - a period where equatorial trade winds strengthen from the west coast of South America and blow across the Pacific, resulting in cooler than normal sea temperatures.
"Wet weather will become widespread in the North Island and upper South Island tomorrow with heavy falls likely overnight into Wednesday," NIWA said on Monday.
In the main centres, Auckland and Hamilton have been told to expect periods of rain on Tuesday and Wednesday. In Wellington, MetService said rain will develop on Tuesday evening, possibly becoming heavy on Wednesday.
