One person is in a critical condition in hospital after a tree fell onto a car on the Southern Motorway last night.
Two others were hurt in the accident, which police blamed on wild weather lashing the city, cutting power to thousands of homes.
A front brought strong winds and heavy rain, including 100 km/h north-easterly gusts.
Police have had multiple callouts related to the strong winds and heavy rain in Auckland. Trees and power lines have fallen, and there have been a number of minor crashes.
A police spokesman said a man in his 40s is in a critical condition after a large tree come down on a car on the Southern Motorway near Rosehill.
Seven people were in the car, and two others had moderate injuries.
The spokesman said the weather has been "extremely inclement", and power outages meant no lights were on along the motorway.
He said the tree "came straight down on top of the car".
A member of the public following the vehicle pulled all seven occupants out after the crash. The passengers were aged from 5 months old to their early 50s.
The road remains closed to south-bound traffic from the Papakura off-ramp, and the serious crash unit is at the scene. Police said the road would remain closed for at least an hour.
Meanwhile, homes in Otahuhu, Mt Wellington, Otara, Mt Albert, Glen Eden, Titirangi, Oratia and others are without power, according to Vector.
The total number of households affected is 4696 according to Vector, and 2692 of those are in Otahuhu/Mt Wellington.
There are also reports of power outages at Pokeno and Tuakau.
A Vector spokeswoman said they were hoping to get power restored before 1am.
"The weather's played havoc with our network. We're doing our best to get the power back on."
She said they would "hopefully get it back on before then, but it depends on the weather".
She said strong winds had brought down power lines, and caused trees to fall on them.
In Otara and Otahuhu, the cause is given as an emergency shutdown for repairs, in Mt Albert the power was shutdown for emergency reasons.
Lines down have caused outages to 322 households in Glen Eden, while feeder faults cut electricity to 780 homes in Tititrangi and 842 in Oratia.
Strong winds and rain are forecast for much of the North Island, and western parts of the South Island, tonight and into Sunday morning.
People took safety indoors while the wild weather wreaked havoc around them, including Lorde's mum Sonja Yelich who took to Twitter.
omg shittiest & shittest weather at the beach house - wind so strong gonna lift the roof - Vic n Angelo playing crib pic.twitter.com/AqzdYLpOwq— Sonja Yelich (@sonjayelich1) January 21, 2017
That rain though. ☔️— Simone McCallum (@simonemccallum) January 21, 2017
Waiting for that power outage.— Josh. G. Spark (@_OUA_) January 21, 2017
@PhilipDuncan It is wild out, wind swirling. I saw a huge blue flash Kelston. Will be lots of damage around!— Zelda Wynn (@ZeldaWynn) January 21, 2017