A severe thunderstorm watch has been issued for the western Bay of Plenty, with heavy rain forecast to hit Tauranga tonight.
The Metservice watch was also issued for the Waikato and Rotorua.
Scattered heavy showers and a few thunderstorms predicted to develop over the eastern Bay of Plenty and Rotorua this afternoon are expected to spread through the remainder of Bay of Plenty and into eastern Waikato in the late afternoon and evening.
The Metservice warned there was a risk of a few severe thunderstorms producing localised downpours of 25 - 35mm/hr through to about 9pm in the Bay west of Whakatane, Rotorua and eastern Waikato.
Rainfall of this intensity could cause flash flooding, especially about low-lying areas such as streams, rivers or narrow valleys, and may also lead to slips, the Metservice warned.
Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain.