Extreme wet weather is predicted to hit Tauranga and the Western Bay of Plenty today.
A severe weather warning was issued by MetService. A severe thunderstorm watch was also put in place.
MetService meteorologist Emma Blades said there was an active frontal system approaching New Zealand yesterday which was expected to cross the country today.
Read more: Car plunges into Tauranga Harbour
There was a risk of thunderstorms for the Bay of Plenty this morning which could become severe for a time producing localised downpours of 25 to 35mm an hour, she said.
The downpours would be possible until afternoon.
Ms Blade said rainfall of that intensity could cause flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips.
Driving conditions would also be hazardous with surface flooding and poor visibility in heavy rain.
Ms Blade said showers would intensify by this morning, bringing thunderstorms.
"Not everybody will get one necessarily because they are very localised but it is going to be wet and everybody will get some rain in the area."
The risk of heavy downpours would be over by this afternoon with the odd shower a possibility this evening, she said.
Tomorrow would bring better weather.
"There would be some fine breaks with the odd shower around as well."
The wet weather was brought on by an area of low pressure with a band of rain wrapped around which was slowly tracking its way across the whole of New Zealand.
"Everywhere is going to be wet with the biggest concentration of rain in the North Island and the west of of the South Island."
Today: 23C high and 18C overnight - rain, chance heavy, easing to showers by the afternoon with northerlies.
Tomorrow: 25C high and 16C overnight - cloudy periods and a few showers. Westerly breezes.
Monday: 24C high and 13C overnight - mainly fine, brief afternoon shower. Westerlies change southerlies
Tuesday: 22C high and 12C overnight - early shower then fine. Southerly breezes.
Wednesday: 21C high and 13C overnight - fine