Frequent thunderstorms are expected to affect the Bay of Plenty from this afternoon.
Metservice warns these storms could bring downpours with hourly rainfall rates exceeding 40mm.
"Rainfall of this intensity can cause surface and/or flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips.
"Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain," A statement said.
The severe thunderstorm watch is in place for many places around the North Island including Rotorua and Taupō.
A large low will move southeastwards across New Zealand on Tuesday, preceded by rain and northerly gales Metservice believe.
Warnings and watches are currently in force for this event.
On Wednesday, the low is expected to move away to the east directing widespread showers and cooler southwesterly gales to many parts of the country.
It was earlier reported, Bay of Plenty residents better have their raincoats handy as heavy rain sweeps across the region.
MetService issued the heavy rain watch for the Bay of Plenty region today, specifically for the Eastern Bay.
Occasional showers, some heavy and thundery are forecast for the rest of today before hard rain and thunderstorms arrive about 2pm tomorrow and last through to 2am on Wednesday.
The dismal weather was brought on by a low over the Tasman Sea and was expected to sweep much of the North Island.
The weather is forecast to improve on Wednesday.
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