Orewa Beach, north of Auckland city, will remain closed to the public on Wednesday, after tidal surges caused significant erosion overnight. A swell of 4m struck about 11pm on Tuesday.
Civil Defence says council inspectors will visit the beach on Wednesday morning to see if it is safe to re-open.
Earlier police were reported to be evacuating houses on two Orewa streets ahead of the surge.
Sixty minor floods were reported across Auckland night as heavy rain and strong winds battered the region on Tuesday night.
Six properties suffered minor damage and repair crews were working throughout the night to repair damaged power lines.
On Tuesday night police said tidal surges were also possible in other low lying communities north of Whangaparaoa, such as Waiwera and Point Wells, until midnight.
The Puhoi River rose rapidly on Tuesday night and officials were working with nearby communities, such as Warkworth, to reduce the risk to property.
Power was cut to 6500 homes and businesses in the wider Auckland region because of heavy rain and strong winds but that was reduced to 4000 later in the night.
A large slip was partially covering State Highway 1 in the vicinity of the Pohuehue Viaduct south of Warkworth and drivers were being asked to avoid the area.
Heavy rain was likely to cause more flooding in west and north Auckland overnight and, earlier, drivers on the North Western Motorway and Tamaki Drive were warned to expect wave splashes.
Winds forecast to reach 130km an hour were expected until about 4am on Wednesday.
Damage south of Auckland
Police received numerous reports of slips, trees down and flooding in the Thames, Coromandel and Hauraki areas.
Sections of State Highway 25 between Thames and Coromandel Town were to remain closed overnight, so inspectors could check that a small tidal surge did not damage the road.
Police warned people throughout the area to stay put if they can and, if they must travel, to drive very slowly because of the hazards.
They said they and other agencies were trying to attend all serious incidents but with the volume being reported, they could not get to every event.
Thames Valley Civil Defence spokesperson Gary Talbot said earlier the Kauaeranga River, on the edge of Thames, had begun to rise and there was concern it would break its banks.
He said Thames Hospital staff took the precaution of lifting some office equipment off floors and took all work vehicles home.
Lines company Vector said customers should be prepared for power cuts.
Roads in other areas
The Transport Agency warned of flooding on State Highway 16 between Helensville and Kaukapakapa overnight, saying the road was suitable for trucks only. Drivers of other vehicles were advised to use Dairy Flat Highway and State Highway 1.
Drivers were also advised to take extra care because of flooding and fallen trees on State Highway 35 from Te Araroa to Tolaga Bay.
Motorcyclists and drivers of high-sided vehicles or towing caravans were warned to take extra care because of strong winds on the Desert Road.
Auckland airport, ports affected
Flights were returning to normal at Auckland Airport on Tuesday night, after delays and diversions earlier.
Ports of Auckland asked the captain of one ship to slow down so that it did not arrive until morning, when the worst of the weather should have passed. As well, workers stacked containers two high, instead of the normal three.
