It's been a wet 24 hours for many parts of the North Island with nearly 100mm of rain falling in inland Taranaki.

MetService said Stratford has had 92mm fall, while Cape Egmont got 66.4mm, Orewa 52mm and Kaitaia 39.6mm.

It said more rain is forecast for much of the North Island and the top of the South Island.

Heavy downpours are expected in Taranaki, mainly north of Opunake to Eltham including the eastern ranges, with up to 150mm expected to fall, and a warning is in place, MetService said.

Driving conditions will be hazardous with surface flooding and poor visibility.

There is likely to be severe thunderstorms in the region, as well as Waitomo and Taumarunui.

There is a thunderstorm risk for most parts of the country today, with a moderate risk of severe thunderstorms for the northern and western parts of the North Island with the potential for rainfall of 25-40mm/hr. Check the risk map for more details at https://t.co/BZWb7ZPiRd ^JM pic.twitter.com/YklPoYwcza — MetService (@MetService) March 23, 2018

Northland, Auckland and Waikato could also get severe thunderstorms.

Outbreaks of heavy rain are expected this afternoon in Marlborough and Nelson, and the Bay of Plenty will get a dousing this evening.

Much of the rest of the country also getting drizzle and showers.

And it has been a cold start in the lower South Island, with Manapouri getting down to 1.8°C and Queenstown on 5.5°, MetService said.