Strong winds and rain have caused damage in Northland, Wellington and Wairarapa overnight and MetService is warning of further hazardous conditions as the remnants of Cyclone Dovi pass over New Zealand today.
Several houses in Plimmerton, near Wellington, were evacuated after a landslide extensively damaged one house and some cars.
Fire and Emergency says the council is now assessing whether the house will still be inhabitable.
Police say other nearby houses have been evacuated as a precaution.
Another slip in Houghton Bay took out one wall of a house. All the occupants are uninjured.
In Lower Hutt, the northbound lanes of State Highway 2 at Korokoro are blocked and diversions are in place after a large slip came down across three lanes of Western Hutt Road just before 12.30am.
And in Northland, about 35 weather-related incidents have been reported to police, including a tree falling and damaging a home in Kauri, Whangarei.
Police, Search and Rescue and Coastguard are also looking into reports of several boats breaking free from moorings at Russell and Opua.
The transport agency Waka Kotahi has issued a strong wind warning for the Auckland Harbour Bridge and lines company Vector is warning people could be without power for days if the weather gets as bad as predicted.
Auckland is expected to get winds of about 120 to 130 gusts an hour, as the former cyclone - now what the MetService calls an extra tropical low - hits.
Waka Kotahi expects the Auckland Harbour Bridge will be closed for several hours, with winds expected to reach around 130 kilometres an hour later this morning.
The transport agency said last night that its bridge safety protocols require the closure of the bridge to traffic when wind gusts reach 90 kilometres an hour.
Auckland Emergency Management group controller Mace Ward said residents needed to check the weather conditions before travelling today.
"If they're driving anywhere, just check the roads first. Waka Kotahi are warning about high gusts on Auckland Harbour Bridge and the roads."
Should the Harbour Bridge be closed, access to the city will be available via the Western Ring Route.
The extra tropical low is expected to hit New Zealand between New Plymouth and Kawhia Harbour, about 10am.
Overnight, firefighters were assisting people with flooding in Masterton, Carterton and South Wairarapa.
Part of State Highway 45 near Rahoutu in Taranaki was also shut by flooding.
Vector put on extra staff to help cope with expected power outages caused by the weather system last night.
The lines company's Marko Simunac said they had been advised the then-cyclone could cause widespread power outages in Auckland which could last for days.
He said West Auckland might be particularly affected.
Simunac says he wanted to reassure people extra crews would be heading out to respond as soon as it was safe to do so.
He said people should not touch any damaged electrical equipment or downed lines, but instead call 111.
All planned outages for maintenance this weekend had been cancelled.