MetService meteorologist Luis Fernandes told the Herald the Harbour Bridge saw gusts of up to 80km/h in the early hours of the morning, and the rest of Auckland should batten down the hatches as the wild weather continues.
"For the rest of the morning, the next few hours at least Auckland is going to stay very wet with persistent, continuous rain - there's going to be no point today when we can say 'oh it's clearing up'."
Fernandes says overnight some exposed areas in Northland had wind gusts over 100km/h, and just under 60mm of rain fell in Kerikeri in the hours from midday yesterday.
The weather is expected to move across the country throughout the day, and Thames Civil Defence controller Garry Towler is urging people to be cautious.
"We still have a lot of rain in the forecast today for both sides of the Coromandel, so keep vigilant, especially on the roads as surface flooding and slips are likely."
MetService says a severe weather warning is in place from 6pm last night through to 9am today.
A heavy burst of rain hit Auckland soon after 5.30am today, causing surface flooding in some CBD streets.
"We are expecting heavy rain from [Monday] morning to around 3pm tomorrow afternoon, with that there could be some thunderstorms and localised downpours also," MetService said.
"Behind that front, the rain turns to showers but they could still be pretty sharp. There is a watch for strong wind from tonight until tomorrow morning."
Waka Kotahi NZ Transport agency said that winds of up to 85km/h could see lanes on the Auckland Harbour Bridge required to close.
Maintenance crews are ready to close lanes if wind gusts exceed the safe use thresholds.
Motorcyclists and drivers in high-sided vehicles should avoid the Harbour Bridge and use the Western Ring on State Highways 16 and 18.
Earlier, heavy rain warnings were issued for other parts of the country including the Far North and Gisborne.
- Additional reporting: RNZ
