"Wind shouldn't be too much of an issue, it's the rain that's more the issue."
Ranger said they hadn't received any reports of tornadoes, but a few thunderstorms had gone through the night, and rainfall had been particularly heavy around Auckland.
"Around 2am to 3am a lot of stations around Auckland have seen anywhere from 20 to 28mm of rain per hour, which is quite decent."
Auckland suffered the most intense rain last night across the country, and "definitely got the worst of it", Ranger said.
Vector's latest figures show around 5000 homes are still without power.
A substation went down in West Auckland last night plunging a "large number" of additional customers into darkness.
A Northern Fire communications spokesman said they'd received 20 to 30 weather-related callouts overnight, and were responding to reports of two cars trapped by flood water in Otahuhu.
"We got the call just before 7am. It looks like they're under a motorway underbridge."
Ranger said Northland and Gisborne could expect some showers today, with heavier showers in the afternoon.
"Southern Taranaki to Wellington is actually looking okay, it will likely fine up today. The South Island is also looking fine."
There's more wild weather to come for Auckland, as another active front moves towards the city on Monday.
Today's wet weather follows a night of weather mayhem that blasted Auckland on Tuesday with winds gusting up to 213km/h at the Manukau Heads.
It tore roofs from houses and uprooted trees that came crashing down on powerlines. At its peak 180,000 homes were without power.
Main centre forecasts today
Whangarei
A few showers, possibly heavy in the evening. A high of 25C.
Auckland
Rain with possible thunderstorms and downpours, easing by evening. A high of 22C
Hamilton
Rain, with possible thunderstorms and downpours and a high of 21C
Tauranga
Rain, with possible thunderstorms and downpours that ease in the afternoon. A high of 18C.
Wellington
Morning cloud, then fine. Light southerlies and a high of 15C.
Christchurch
Cloudy periods, a few showers about and a high of 13C.
Dunedin
Fine spells but a shower or two until evening, a high of 12C.
Queenstown
Fine with light winds a high of 12C.