Heavy rain is on the way for parts of both islands today, MetService forecasts.
A severe weather warning has been issued for Fiordland, Southland, Bay Of Plenty, Rotorua, and Nelson.
Forecaster Oliver Druce says a front over southern Fiordland should move slowly north and weaken today.
"Another front is expected to swing southwards over the North Island this evening and tonight bringing widespread rain to northern and central New Zealand.
"A burst of heavy rain is forecast for northwest Nelson from later this afternoon until early Wednesday morning. And for Bay of Plenty, heavy rain is expected overnight.