Nearly 2000 Northland homes are without power on as high winds continue to cause damage to powerlines in the region.
The western part of the Bay of Islands was the worst affected by the storm on Sunday night, with more than 1000 homes cut off.
There were also patches of power outages across the northern part of Auckland, but Vector was unable to confirm how many were affected.
In Northland, trees and vegetation had done most of the damage to the power network, a Top Energy spokesperson said. Its crews had been working in challenging conditions for most of the day, and were standing down for Sunday night, but would be back at first light on Monday if the conditions are safe.
The tail of ex-Tropical Cyclone Lola, which caused extensive damage as it smashed through parts of Vanuatu earlier this week, has merged with another trough as it bears down on the upper North Island.
MetService has issued several severe weather warnings as a result, with heavy rain warnings in place for Northland and Coromandel Peninsula from later Sunday into Monday morning and for Tai Rāwhiti/Gisborne, from Tolaga Bay northwards, through Monday and into the evening.
Lanes have been closed on and off on the Auckland Harbour Bridge on Sunday and were likely to continue with intermittent closures overnight.
Wind gusts reached 95kmh over the bridge.
Waka Kotahi is still urging motorists to take care, especially high-sided vehicles and motorcycles.
A strong wind warning is also in place for Northland, with easterly gales hitting Auckland, north of Whangaparaoa, Great Barrier Island and Coromandel Peninsula as the weather system slowly moves south.
MetService meteorologist Clare O'Connor said the remnants of Cyclone Lola had "picked up a bit of another system" as it approached New Zealand and the combination of the two was causing the bad weather.
While things would not get as bad as they had in Vanuatu, people should keep up to date with the latest forecasts, she said.
Gisborne would be next in line for heavy rain from early on Monday morning, persisting into the evening, MetService said.
Heavy rain watches were also due to come into effect for the area of Tai Rāwhiti - south of Tolaga Bay - and the western ranges of Hawke's Bay, from late on Monday morning.
For the most up to date MetService warnings visit their website.