Large parts of the North Island could be in for heavy downpours and forecasters are warning people to be on the lookout for severe thunderstorms.
The Metservice on Tuesday issued a severe thunderstorm watch for Auckland down to the Wairarapa and northern South Island.
Scattered heavy showers and thunderstorms will continue into the evening in most places, says forecaster John Crouch.
Many of these thunderstorms are expected to be severe, especially inland and particularly about the central North Island, where rainfall rates of 20 to 40 mm/hr (or even 50+ mm/hr) were likely.
"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," Mr Crouch said.
"Driving conditions will also be hazardous with surface flooding and poor visibility in heavy rain."