Rotorua is now on thunderstorm watch, in addition to the heavy rain warning issued by the MetService.

'Thunderstorms are likely to affect the area this morning, afternoon and into the evening,” says a statement from the weather organisation.

'Severe thunderstorms are possible with downpours bringing rainfall intensities of 25 to 40mm per hour.

'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.”

A thunderstorm watch has been issued for the following regions:

Auckland

Coromandel Peninsula

Waikato

Waitomo

Taumarunui

Bay of Plenty

Rotorua

Taupo

Hawke's Bay

Taranaki

Taihape