Heavy rain is continuing to lash parts of the North Island today, and forecasters are warning that the worst is yet to come.
A low-pressure system originating from the tropics is moving towards New Zealand, bringing ongoing heavy rain.
Northland and Coromandel Peninsula are under orange heavy rain warnings and MetService says there's a high chance they will be upgraded to the highest red warnings.
The forecaster has also issued strong wind watches for Auckland and Waikato from 8am, while orange heavy rain warnings for Bay of Plenty and Gisborne come into effect this afternoon.
There are also heavy rain watches in place for most of the upper South Island, including Canterbury, Westland, Buller, Nelson and Tasman.
Civil Defence is urging people to prepare for the storm, with widespread rain expected to continue into Thursday.
Emergency Management and Recovery Minister Mark Mitchell said he was most worried about Northland and Ōakura and the surrounding areas as "they're basically fully saturated in terms of the ground... and we've got more coming".
He said the areas had been hit "very hard, lots of slips", and contractors were working to open roads and get access for people.
He urged people to think about their safety and said they should be prepared to leave if necessary, advising them to "have a grab bag ready to go".
"If you want to move, now is the time to do it."
Mitchell said it was to anticipate how much water there would be or where it was going to hit, adding that weather warnings and watches were "not a perfect science".
"I get reports and updates every day of warnings, watches, thunderstorms, possible thunderstorms... everyone tries to be as vigilant as they can... but it's not a perfect science."
- RNZ/Allied Media
