Heavy rain and thundery downpours are expected to batter the country on Mother's Day.
A complex trough over the Tasman Sea is expected to slowly move over New Zealand from today through to early Tuesday.
MetService said this is expected to bring periods of heavy rain, with the heaviest falls expected in Taranaki and Waitomo, where a severe weather warning is in place.
It is predicted that 250 to 350mm of rain may fall over higher slopes of Mount Taranaki. And MetService said this rain is likely to be accompanied by squally thunderstorms.
Elsewhere heavy falls are likely in Fiordland, Westland, Buller, northwest Nelson, Marlborough Sounds, Horowhenua, Kapiti Coast, Bay of Plenty, northern Wellington and the Tararua Range this afternoon and Monday.
Periods of thundery rain are also forecast from about midday today for the central North Island hill country.
This affects areas from the headwaters of the Whanganui River across to Tongariro National Park.
MetService said rivers and streams may rise rapidly, and slips, surface and flash flooding were possible.
Find the latest weather forecast in your area here.