The forecaster warned that thunderstorms and downpours are also possible.
A main route through the Coromandel Peninsula was closed after several severe weather events in just weeks.
State Highway 25A is one of the main tourist routes for holidaymakers heading to the Thames-Coromandel region, but it was closed in January after the formation of deep cracks, slips and flooding damage from ex-Cyclone Hale.
The road is expected to be closed for up to a year.
Police were encouraging people to be safe and consider the weather before leaving home.
“Police urge motorists to take care on the roads and drive to the conditions,” said a spokesperson.
“Ensure you maintain a good following distance between other vehicles. In bad weather increase your following distance to allow more time for stopping.
“It’s a good idea to plan ahead for your journeys and make sure you factor in extra time for potential delays.
“Take care and when you’re out on the roads make sure you’re considerate of others.”
For updates on road closures, and to plan ahead for potential delays caused by slips or roadworks visit www.journeys.nzta.govt.nz
Civil Defence is urging people to keep up to date with MetService forecasts and get ready before any storm.
“Work out what supplies you might need and make a plan. Have materials and tools ready to repair windows, such as tarpaulins, boards and duct tape,” the agency’s safety advice says.
“Identify a safe place in your home to gather during a thunderstorm. This should be a place where there are no windows, skylights, or glass doors. These could break in strong winds or hail and cause damage or injury.
“Be aware that storms can trigger floods and landslides. Make sure you know how to respond.”